diff --git a/backend/package.json b/backend/package.json
index 819e97d..63a6dc5 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -15,7 +15,7 @@
     "start:debug": "nest start --debug --watch",
     "start:prod": "node dist/main",
     "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
-    "test": "jest --detectOpenHandles",
+    "test": "jest",
     "test:watch": "jest --watch",
     "test:cov": "jest --coverage",
     "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
@@ -70,7 +70,15 @@
       "json",
       "ts"
     ],
-    "rootDir": "src",
+    "roots": [
+      "<rootDir>"
+    ],
+    "modulePaths": [
+      "<rootDir>"
+    ],
+    "moduleDirectories": [
+      "node_modules"
+    ],
     "testRegex": ".*\\.spec\\.ts$",
     "transform": {
       "^.+\\.(t|j)s$": "ts-jest"
diff --git a/backend/src/search/entities/crossRef.entity.ts b/backend/src/search/entities/crossRef.entity.ts
index 05707fb..919b2dd 100644
--- a/backend/src/search/entities/crossRef.entity.ts
+++ b/backend/src/search/entities/crossRef.entity.ts
@@ -2,14 +2,32 @@ export class PaperInfo {
   title?: string;
   authors?: string[];
   doi?: string;
+
+  constructor(body: PaperInfo) {
+    this.title = body.title;
+    this.authors = body.authors;
+    this.doi = body.doi;
+  }
 }
 export class PaperInfoExtended extends PaperInfo {
   publishedAt?: string;
   citations?: number;
   references?: number;
+
+  constructor(body: PaperInfoExtended) {
+    super(body);
+    this.publishedAt = body.publishedAt;
+    this.citations = body.citations;
+    this.references = body.references;
+  }
 }
 export class PaperInfoDetail extends PaperInfoExtended {
   referenceList?: ReferenceInfo[];
+
+  constructor(body: PaperInfoDetail) {
+    super(body);
+    this.referenceList = body.referenceList;
+  }
 }
 export interface ReferenceInfo {
   issn?: string;
@@ -21,7 +39,7 @@ export interface ReferenceInfo {
   'doi-asserted-by'?: string;
   'first-page'?: string;
   isbn?: string;
-  doi?: string;
+  DOI?: string;
   component?: string;
   'article-title'?: string;
   'volume-title'?: string;
diff --git a/backend/src/search/search.controller.ts b/backend/src/search/search.controller.ts
index 39d17b4..567e871 100644
--- a/backend/src/search/search.controller.ts
+++ b/backend/src/search/search.controller.ts
@@ -1,4 +1,4 @@
-import { Controller, Get, Query, UsePipes, ValidationPipe } from '@nestjs/common';
+import { Controller, Get, NotFoundException, Query, UsePipes, ValidationPipe } from '@nestjs/common';
 import { SearchService } from './search.service';
 import { AutoCompleteDto, GetPaperDto, SearchDto } from './entities/search.dto';
 import { SearchTotalHits } from '@elastic/elasticsearch/lib/api/types';
@@ -17,7 +17,8 @@ export class SearchController {
     if (elasticDataCount > 0) {
       return elastic.hits.hits.map((paper) => paper._source);
     }
-    const { items, totalItems } = await this.searchService.getCrossRefAutoCompleteData(keyword);
+    const selects = ['title', 'author', 'DOI'];
+    const { items, totalItems } = await this.searchService.getCrossRefData(keyword, 5, 1, selects);
     const papers = this.searchService.parseCrossRefData(items, this.searchService.parsePaperInfo);
     this.searchService.crawlAllCrossRefData(keyword, totalItems, 1000);
     return papers;
@@ -27,14 +28,20 @@ export class SearchController {
   @UsePipes(new ValidationPipe({ transform: true }))
   async getPapers(@Query() query: SearchDto) {
     const { keyword, rows, page } = query;
-    const { items, totalItems } = await this.searchService.getCrossRefData(keyword, rows, page);
+    const selects = ['title', 'author', 'created', 'is-referenced-by-count', 'references-count', 'DOI'];
+    const { items, totalItems } = await this.searchService.getCrossRefData(keyword, rows, page, selects);
+    const totalPages = Math.ceil(totalItems / rows);
+    if (page > totalPages) {
+      throw new NotFoundException(`page(${page})는 ${totalPages} 보다 클 수 없습니다.`);
+    }
     const papers = this.searchService.parseCrossRefData(items, this.searchService.parsePaperInfoExtended);
     this.rankingService.insertRedis(keyword);
+
     return {
       papers,
       pageInfo: {
         totalItems,
-        totalPages: Math.ceil(totalItems / rows),
+        totalPages,
       },
     };
   }
diff --git a/backend/src/search/search.module.ts b/backend/src/search/search.module.ts
index c15dce3..3361bcb 100644
--- a/backend/src/search/search.module.ts
+++ b/backend/src/search/search.module.ts
@@ -8,7 +8,12 @@ import { ScheduleModule } from '@nestjs/schedule';
 import { RankingService } from 'src/ranking/ranking.service';
 @Module({
   imports: [
-    HttpModule,
+    HttpModule.register({
+      timeout: 20000,
+      headers: {
+        'User-Agent': `Axios/1.1.3(mailto:${process.env.MAIL_TO})`,
+      },
+    }),
     ElasticsearchModule.registerAsync({
       useFactory: () => ({
         node: process.env.ELASTIC_HOST,
diff --git a/backend/src/search/search.service.ts b/backend/src/search/search.service.ts
index effc444..c7c3847 100644
--- a/backend/src/search/search.service.ts
+++ b/backend/src/search/search.service.ts
@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { Injectable, RequestTimeoutException } from '@nestjs/common';
 import { HttpService } from '@nestjs/axios';
 import {
   CrossRefResponse,
@@ -15,22 +15,12 @@ import { SearchHit } from '@elastic/elasticsearch/lib/api/types';
 @Injectable()
 export class SearchService {
   constructor(private readonly httpService: HttpService, private readonly esService: ElasticsearchService) {}
-  async getCrossRefAutoCompleteData(keyword: string) {
-    const crossRefdata = await this.httpService.axiosRef.get<CrossRefResponse>(CROSSREF_API_URL(keyword));
-    const items = crossRefdata.data.message.items;
-    const totalItems = crossRefdata.data.message['total-results'];
-    return { items, totalItems };
-  }
-
-  async getCrossRefData(keyword: string, rows: number, page: number) {
-    const crossRefdata = await this.httpService.axiosRef.get<CrossRefResponse>(
-      CROSSREF_API_URL(
-        keyword,
-        rows,
-        ['title', 'author', 'created', 'is-referenced-by-count', 'references-count', 'DOI'],
-        page,
-      ),
-    );
+  async getCrossRefData(keyword: string, rows: number, page: number, selects?: string[]) {
+    const crossRefdata = await this.httpService.axiosRef
+      .get<CrossRefResponse>(CROSSREF_API_URL(keyword, rows, page, selects))
+      .catch((err) => {
+        throw new RequestTimeoutException(err.message);
+      });
     const items = crossRefdata.data.message.items;
     const totalItems = crossRefdata.data.message['total-results'];
     return { items, totalItems };
@@ -42,21 +32,23 @@ export class SearchService {
         .fill(0)
         .map((v, i) => {
           CROSSREF_CACHE_QUEUE.push(
-            CROSSREF_API_URL(
-              keyword,
-              rows,
-              ['title', 'author', 'created', 'is-referenced-by-count', 'references-count', 'DOI'],
-              i + 1,
-            ),
+            CROSSREF_API_URL(keyword, rows, i + 1, [
+              'title',
+              'author',
+              'created',
+              'is-referenced-by-count',
+              'references-count',
+              'DOI',
+            ]),
           );
         }),
     );
   }
   parseCrossRefData<T extends PaperInfo>(items: CrossRefItem[], parser: (item: CrossRefItem) => T) {
-    return items.map(parser).filter((info) => info.title || info.authors?.length > 0);
+    return items.map(parser).filter((info) => info.title);
   }
   parsePaperInfo = (item: CrossRefItem) => {
-    const paperInfo = {
+    const data = {
       title: item.title?.[0],
       authors: item.author?.reduce((acc, cur) => {
         const authorName = `${cur.name ? cur.name : cur.given ? cur.given + ' ' : ''}${cur.family || ''}`;
@@ -64,42 +56,45 @@ export class SearchService {
         return acc;
       }, []),
       doi: item.DOI,
-    } as PaperInfo;
+    };
 
-    return paperInfo;
+    return new PaperInfo(data);
   };
   parsePaperInfoExtended = (item: CrossRefItem) => {
-    const paperInfo = {
+    const data = {
       ...this.parsePaperInfo(item),
       publishedAt: item.created?.['date-time'],
       citations: item['is-referenced-by-count'],
       references: item['references-count'],
-    } as PaperInfoExtended;
+    };
 
-    return paperInfo;
+    return new PaperInfoExtended(data);
   };
   parsePaperInfoDetail = (item: CrossRefItem) => {
-    const referenceList = item['reference'].map((reference) => {
-      return {
-        title:
-          reference['article-title'] ||
-          reference['journal-title'] ||
-          reference['series-title'] ||
-          reference['volume-title'],
-        doi: reference['doi'],
-        // TODO: 현재 원하는 정보를 얻기 위해서는 해당 reference에 대한 정보를 crossref에 다시 요청해야함
-        author: reference['author'],
-        publishedAt: reference['year'],
-        citations: 0,
-        references: 0,
-      };
-    });
-    const paperInfo = {
+    const referenceList =
+      item['reference']?.map((reference) => {
+        return {
+          key: reference['DOI'] || reference.key || reference.unstructured,
+          title:
+            reference['article-title'] ||
+            reference['journal-title'] ||
+            reference['series-title'] ||
+            reference['volume-title'] ||
+            reference.unstructured,
+          doi: reference['DOI'],
+          // TODO: 현재 원하는 정보를 얻기 위해서는 해당 reference에 대한 정보를 crossref에 다시 요청해야함
+          author: reference['author'],
+          publishedAt: reference['year'],
+          citations: 0,
+          references: 0,
+        };
+      }) || [];
+    const data = {
       ...this.parsePaperInfoExtended(item),
       referenceList,
-    } as PaperInfoDetail;
+    };
 
-    return paperInfo;
+    return new PaperInfoDetail(data);
   };
 
   async getPaper(doi: string) {
diff --git a/backend/src/search/tests/search.controller.spec.ts b/backend/src/search/tests/search.controller.spec.ts
index 8796ac6..d08f477 100644
--- a/backend/src/search/tests/search.controller.spec.ts
+++ b/backend/src/search/tests/search.controller.spec.ts
@@ -1,64 +1,133 @@
 import { SearchController } from '../search.controller';
 import { SearchService } from '../search.service';
 import { HttpService } from '@nestjs/axios';
-import { CrossRefResponse, PaperInfo, PaperInfoExtended } from '../entities/crossRef.entity';
-import mockData from './crossref.mock';
+import { PaperInfo, PaperInfoDetail, PaperInfoExtended } from '../entities/crossRef.entity';
 import { Test, TestingModule } from '@nestjs/testing';
+import { ElasticsearchService } from '@nestjs/elasticsearch';
+import { mockElasticService, mockHttpService, mockRankingService } from './search.service.mock';
+import { RankingService } from '../../ranking/ranking.service';
+import { INestApplication, ValidationPipe } from '@nestjs/common';
+import * as request from 'supertest';
+
 describe('SearchController', () => {
   let controller: SearchController;
+  let service: SearchService;
+  let app: INestApplication;
 
-  beforeEach(async () => {
-    const httpService = new HttpService();
-    jest.spyOn(httpService['axiosRef'], 'get').mockImplementation((url: string) => {
-      const params = new URLSearchParams(new URL(url).search);
-      const keyword = params.get('query');
-      const rows = parseInt(params.get('rows'));
-      const selects = params.get('select').split(',');
-      const items = mockData.message.items.slice(0, rows).map((item, i) => {
-        return selects.reduce((acc, select) => {
-          if (select === 'title') item[select] = [`${keyword}-${i}`];
-          acc[select] = item[select];
-          return acc;
-        }, {});
-      });
+  let spyGetElasticSearch: jest.SpyInstance;
+  let spyGetCrossRefData: jest.SpyInstance;
+  const keyword = 'coffee';
 
-      return Promise.resolve<{ data: CrossRefResponse }>({
-        data: { message: { 'total-results': mockData.message['total-results'], items } },
-      });
-    });
+  beforeEach(async () => {
+    const httpService = mockHttpService();
+    const rankingService = mockRankingService();
+    const elasticService = mockElasticService();
     const module: TestingModule = await Test.createTestingModule({
       controllers: [SearchController],
       providers: [
         SearchService,
+        {
+          provide: RankingService,
+          useValue: rankingService,
+        },
         {
           provide: HttpService,
           useValue: httpService,
         },
+        {
+          provide: ElasticsearchService,
+          useValue: elasticService,
+        },
       ],
     }).compile();
     controller = module.get(SearchController);
-  });
+    service = module.get(SearchService);
+    spyGetElasticSearch = jest.spyOn(service, 'getElasticSearch');
+    spyGetCrossRefData = jest.spyOn(service, 'getCrossRefData');
 
-  it('search controller 정의', () => {
-    expect(controller).toBeDefined();
+    app = module.createNestApplication();
+    app.useGlobalPipes(new ValidationPipe());
+    await app.init();
   });
+  afterEach(() => app.close());
+
+  describe('/search/auto-complete', () => {
+    it('getAutoCompletePapers - keyword=coffee 일 때 PaperInfo[]를 return', async () => {
+      // Case 1. elasticsearch에 data가 없을 경우
+      const itemsByCrossRef = await controller.getAutoCompletePapers({ keyword });
+      expect(itemsByCrossRef.length).toBe(5);
+      itemsByCrossRef.forEach((item) => {
+        expect(item instanceof PaperInfo).toBe(true);
+      });
 
-  it('getAutoCompletePapers - keyword=coffee 일 때 PaperInfo[]를 return', async () => {
-    const keyword = 'coffee';
-    const items = await controller.getAutoCompletePapers(keyword);
-    expect(items.length).toBe(5);
-    items.forEach((item) => {
-      expect(item).toBeInstanceOf(PaperInfo);
+      // Case 2. elasticsearch에 data가 있는 경우
+      const itemsByElasticsearch = await controller.getAutoCompletePapers({ keyword });
+      expect(itemsByElasticsearch.length).toBe(5);
+      itemsByElasticsearch.forEach((item) => {
+        expect(item instanceof PaperInfo).toBe(true);
+      });
+
+      expect(spyGetElasticSearch).toBeCalledTimes(2);
+      expect(spyGetCrossRefData).toBeCalledTimes(1);
+    });
+    it('keyword 미포함시 error - GET /search/auto-complete?keyword=', () => {
+      const url = (keyword: string) => `/search/auto-complete?keyword=${keyword}`;
+      request(app.getHttpServer()).get(url('')).expect(400);
+    });
+  });
+  describe('/search', () => {
+    const DEFAULT_ROWS = 20;
+    const TOTAL_ITEMS = 28810;
+    it(`getPapers - keyword='coffee' 일 때 PaperInfoExtended[]를 return`, async () => {
+      const keyword = 'coffee';
+      const { papers: items, pageInfo } = await controller.getPapers({ keyword, rows: 20, page: 1 });
+      expect(items.length).toBe(DEFAULT_ROWS);
+      expect(pageInfo.totalItems).toBe(TOTAL_ITEMS);
+      items.forEach((item) => {
+        expect(item).toBeInstanceOf(PaperInfoExtended);
+      });
+      // TODO: elasticsearch로 검색?
+      expect(spyGetElasticSearch).toBeCalledTimes(0);
+      expect(spyGetCrossRefData).toBeCalledTimes(1);
+    });
+    it('keyword 미포함시 error - GET /search?keyword=', () => {
+      const url = (keyword: string) => `/search?keyword=${keyword}`;
+      request(app.getHttpServer()).get(url('')).expect(400);
+    });
+    it('rows<=0 이거나, rows 값이 integer가 아닐 경우 error - GET /search?keyword=coffee&rows=<rows>', () => {
+      const url = (rows: string | number) => `/search?keyword=${keyword}&rows=${rows}`;
+      const rowsNotAvailables = [-1, -0.1, '0', 'value'];
+      rowsNotAvailables.forEach((value) => {
+        request(app.getHttpServer()).get(url(value)).expect(400);
+      });
+    });
+    it('page<=0 이거나, page 값이 integer가 아닐 경우 error - GET /search?keyword=coffee&page=<page>', () => {
+      const url = (page: string | number) => `/search?keyword=${keyword}&page=${page}`;
+      const pageNotAvailables = [-1, -0.1, '0', 'value'];
+      pageNotAvailables.forEach((value) => {
+        request(app.getHttpServer()).get(url(value)).expect(400);
+      });
+    });
+    it('page>max 이면 error - GET /search?keyword=coffee&page=<page>', () => {
+      const url = (page: string | number) => `/search?keyword=${keyword}&page=${page}`;
+      const maxPage = Math.ceil(TOTAL_ITEMS / DEFAULT_ROWS);
+      request(app.getHttpServer())
+        .get(url(maxPage + 1))
+        .expect(404);
     });
   });
 
-  it(`getAutoCompletePapers - keyword='' 일 때 PaperInfoExtended[]를 return`, async () => {
-    const keyword = 'coffee';
-    const { papers: items, pageInfo } = await controller.getPapers(keyword);
-    expect(items.length).toBe(20);
-    expect(pageInfo.totalItems).toBe(28810);
-    items.forEach((item) => {
-      expect(item).toBeInstanceOf(PaperInfoExtended);
+  describe('/search/paper', () => {
+    it(`getPaper - doi=10.1234/some_doi 일 때 PaperInfoDetail을 return`, async () => {
+      const doi = '10.1234/some_doi';
+      const paper = await controller.getPaper({ doi });
+      expect(paper.references).toBe(5);
+      expect(paper.referenceList.length).toBe(5);
+      expect(paper).toBeInstanceOf(PaperInfoDetail);
+    });
+    it('doi가 입력되지 않을 경우 error - GET /search/paper?doi=', () => {
+      const url = (keyword: string) => `/search/paper?doi=${keyword}`;
+      request(app.getHttpServer()).get(url('')).expect(400);
     });
   });
 });
diff --git a/backend/src/search/tests/search.service.mock.ts b/backend/src/search/tests/search.service.mock.ts
new file mode 100644
index 0000000..356617b
--- /dev/null
+++ b/backend/src/search/tests/search.service.mock.ts
@@ -0,0 +1,72 @@
+import mockCrossRefData from './crossref.mock';
+import mockSearchData from './searchdata.mock';
+import { HttpService } from '@nestjs/axios';
+import { CrossRefPaperResponse, CrossRefResponse, PaperInfo } from '../entities/crossRef.entity';
+
+export function mockHttpService() {
+  const httpService = new HttpService();
+  jest.spyOn(httpService['axiosRef'], 'get').mockImplementation((url: string) => {
+    const params = new URLSearchParams(new URL(url).search);
+    const keyword = params.get('query');
+    if (keyword === null) {
+      const item = mockCrossRefData.message.items[0];
+      return Promise.resolve<{ data: CrossRefPaperResponse }>({
+        data: { message: item },
+      });
+    }
+    const rows = parseInt(params.get('rows'));
+    const selects = params.get('select').split(',');
+    const items = mockCrossRefData.message.items.slice(0, rows).map((item, i) => {
+      return selects.reduce((acc, select) => {
+        if (select === 'title') item[select] = [`${keyword}-${i}`];
+        acc[select] = item[select];
+        return acc;
+      }, {});
+    });
+
+    return Promise.resolve<{ data: CrossRefResponse }>({
+      data: { message: { 'total-results': mockCrossRefData.message['total-results'], items } },
+    });
+  });
+  return httpService;
+}
+
+export function mockElasticService() {
+  // TODO: should mockup index?
+  const index = jest.fn().mockResolvedValue(() => {
+    return true;
+  });
+  const search = jest.fn();
+  search
+    .mockResolvedValueOnce({
+      hits: {
+        total: {
+          value: 0,
+        },
+      },
+    })
+    .mockResolvedValue({
+      hits: {
+        total: {
+          value: 222,
+        },
+        hits: mockSearchData
+          .map((data) => {
+            return {
+              _source: new PaperInfo(data),
+            };
+          })
+          .slice(0, 5),
+      },
+    });
+  const elasticService = { index, search };
+  return elasticService;
+}
+
+export function mockRankingService() {
+  const insertRedis = jest.fn().mockResolvedValue(() => {
+    return true;
+  });
+  const rankingService = { insertRedis };
+  return rankingService;
+}
diff --git a/backend/src/search/tests/searchdata.mock.ts b/backend/src/search/tests/searchdata.mock.ts
new file mode 100644
index 0000000..8a38a6c
--- /dev/null
+++ b/backend/src/search/tests/searchdata.mock.ts
@@ -0,0 +1,172 @@
+import { PaperInfoExtended } from '../entities/crossRef.entity';
+
+export default [
+  {
+    title:
+      'Thermodynamic Properties of Systems Comprising Esters: Experimental Data and Modeling with PC-SAFT and SAFT Mie',
+    doi: '10.1021/acs.iecr.9b00714.s001',
+    publishedAt: '2020-04-09T15:47:35Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title:
+      'Comparison of CP-PC-SAFT and PC-SAFT with k12 = 0 and PPR78 in Predicting Binary Systems of Hydrocarbons with Squalane, ndodecylbenzene, cis-decalin, Tetralin, and Naphthalene at High Pressures',
+    doi: '10.1021/acs.iecr.1c03486.s001',
+    publishedAt: '2021-10-25T13:26:30Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Boyle temperature from SAFT, PC-SAFT and SAFT-VR equations of state',
+    authors: ['Samane Zarei', 'Farzaneh Feyzi'],
+    doi: '10.1016/j.molliq.2013.06.010',
+    publishedAt: '2013-07-04T20:46:55Z',
+    citations: 15,
+    references: 44,
+  },
+  {
+    title: 'Comparison of SAFT-VR-Mie and CP-PC-SAFT in Estimating the Phase Behavior of Acetone + nAlkane Systems',
+    doi: '10.1021/acs.iecr.0c04435.s001',
+    publishedAt: '2020-11-25T06:50:17Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Modeling of carbon dioxide and water sorption in glassy polymers through PC-SAFT and NET PC-SAFT',
+    authors: ['Liang Liu', 'Sandra E. Kentish'],
+    doi: '10.1016/j.polymer.2016.10.002',
+    publishedAt: '2016-10-09T04:06:52Z',
+    citations: 10,
+    references: 60,
+  },
+  {
+    title: 'Thermodynamic Modeling of Triglycerides using PC-SAFT',
+    doi: '10.1021/acs.jced.8b01046.s001',
+    publishedAt: '2020-04-09T21:21:54Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Vle Property Measurements and  Pc-Saft/ Cp- Pc-Saft/ E-Ppr78 Modeling of the Co2 + N-Tetradecane Mixture',
+    authors: [
+      'Vener Khairutdinov',
+      'Farid Gumerov',
+      'Ilnar Khabriev',
+      'Talgat Akhmetzyanov',
+      'Ilfat Salikhov',
+      'Ilya Polishuk',
+      'ilmutdin abdulagatov',
+    ],
+    doi: '10.2139/ssrn.4188488',
+    publishedAt: '2022-08-13T13:32:29Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Application of PC-SAFT to glycol containing systems – PC-SAFT towards a predictive approach',
+    authors: ['Andreas Grenner', 'Georgios M. Kontogeorgis', 'Nicolas von Solms', 'Michael L. Michelsen'],
+    doi: '10.1016/j.fluid.2007.04.025',
+    publishedAt: '2007-04-30T14:49:55Z',
+    citations: 37,
+    references: 37,
+  },
+  {
+    title: 'PC-SAFT Modeling of CO2 Solubilities in Deep Eutectic Solvents',
+    doi: '10.1021/acs.jpcb.5b07888.s001',
+    publishedAt: '2020-04-08T16:19:35Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title:
+      'IPC-SAFT: An Industrialized Version of the Volume-Translated PC-SAFT Equation of State for Pure Components, Resulting from Experience Acquired All through the Years on the Parameterization of SAFT-Type and Cubic Models',
+    doi: '10.1021/acs.iecr.9b04660.s001',
+    publishedAt: '2020-04-07T21:03:41Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title:
+      'Parameterization of SAFT Models: Analysis of Different Parameter Estimation Strategies and Application to the Development of a Comprehensive Database of PC-SAFT Molecular Parameters',
+    doi: '10.1021/acs.jced.0c00792.s001',
+    publishedAt: '2020-11-30T23:27:16Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title:
+      'Implementation of CP-PC-SAFT and CS-SAFT-VR-Mie for Predicting Thermodynamic Properties of C1C3 Halocarbon Systems. I. Pure Compounds and Mixtures with Nonassociating Compounds',
+    doi: '10.1021/acs.iecr.1c01700.s001',
+    publishedAt: '2021-06-28T13:45:30Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Predicting the Solubility of CO2 in Toluene + Ionic Liquid Mixtures with PC-SAFT',
+    doi: '10.1021/acs.iecr.7b01497.s001',
+    publishedAt: '2020-04-06T18:59:00Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title:
+      'Evaluation of SAFT and PC-SAFT models for the description of homo- and co-polymer solution phase equilibria',
+    authors: ['Theodora Spyriouni', 'Ioannis G. Economou'],
+    doi: '10.1016/j.polymer.2005.09.001',
+    publishedAt: '2005-09-23T13:48:14Z',
+    citations: 19,
+    references: 27,
+  },
+  {
+    title: 'VLE property measurements and PC-SAFT/ CP- PC-SAFT/ E-PPR78 modeling of the CO2 + n-tetradecane mixture',
+    authors: [
+      'Vener F. Khairutdinov',
+      'Farid M. Gumerov',
+      'Ilnar Sh. Khabriev',
+      'Talgat R. Akhmetzyanov',
+      'Ilfat Z. Salikhov',
+      'Ilya Polishuk',
+      'Ilmutdin M. Abdulagatov',
+    ],
+    doi: '10.1016/j.fluid.2022.113615',
+    publishedAt: '2022-09-20T01:54:20Z',
+    citations: 0,
+    references: 79,
+  },
+  {
+    title: 'Thermodynamic Properties of 1Hexyl-3-methylimidazolium Nitrate and 1Alkanols Mixtures: PC-SAFT Model',
+    doi: '10.1021/acs.jced.9b00507.s001',
+    publishedAt: '2020-04-08T11:44:12Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Integrated Working Fluids and Process Optimization for Refrigeration Systems Using Polar PC-SAFT',
+    doi: '10.1021/acs.iecr.1c03624.s001',
+    publishedAt: '2021-11-29T13:45:54Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Thermodynamic and Transport Properties of Formic Acid and 2Alkanol Mixtures: PC-SAFT Model',
+    doi: '10.1021/acs.jced.2c00496.s001',
+    publishedAt: '2022-11-09T21:00:10Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: '5Hydroxymethylfurfural Synthesis in Nonaqueous Two-Phase Systems (NTPS)PC-SAFT Predictions and Validation',
+    doi: '10.1021/acs.oprd.0c00072.s001',
+    publishedAt: '2020-05-26T16:46:36Z',
+    citations: 0,
+    references: 0,
+  },
+  {
+    title: 'Investigating Various Parametrization Strategies for Pharmaceuticals within the PC-SAFT Equation of State',
+    doi: '10.1021/acs.jced.0c00707.s001',
+    publishedAt: '2020-09-30T13:48:49Z',
+    citations: 0,
+    references: 0,
+  },
+] as PaperInfoExtended[];
diff --git a/backend/src/tests/search.controller.e2e.spec.ts b/backend/src/tests/search.controller.e2e.spec.ts
deleted file mode 100644
index e349122..0000000
--- a/backend/src/tests/search.controller.e2e.spec.ts
+++ /dev/null
@@ -1,67 +0,0 @@
-import { Test, TestingModule } from '@nestjs/testing';
-import { SearchController } from '../search/search.controller';
-import { SearchService } from '../search/search.service';
-import { PaperInfo, PaperInfoExtended } from '../search/entities/crossRef.entity';
-import { HttpModule } from '@nestjs/axios';
-import { INestApplication, ValidationPipe } from '@nestjs/common';
-import * as request from 'supertest';
-
-describe('(e2e) SearchController - /search/auto-complete', () => {
-  let app: INestApplication;
-  const url = (keyword: string) => `/search/auto-complete?keyword=${keyword}`;
-
-  beforeEach(async () => {
-    const module: TestingModule = await Test.createTestingModule({
-      imports: [HttpModule],
-      controllers: [SearchController],
-      providers: [SearchService],
-    }).compile();
-    app = module.createNestApplication();
-    app.useGlobalPipes(new ValidationPipe());
-    await app.init();
-  });
-
-  it('keyword 포함 검색 - GET /search/auto-complete?keyword=coffee', async () => {
-    const keyword = 'coffee';
-    const res = await request(app.getHttpServer()).get(url(keyword));
-    const items: PaperInfo[] = JSON.parse(res.text);
-    expect(items.length).toBe(5);
-    // TODO: type check
-    // items.forEach((item) => {
-    //   expect(item).toBeInstanceOf(PaperInfo);
-    // });
-  });
-  it('keyword 미포함시 error - GET /search/auto-complete?keyword=', () => {
-    return request(app.getHttpServer()).get(url('')).expect(400);
-  });
-});
-
-describe('(e2e) SearchController - /search', () => {
-  let app: INestApplication;
-  const url = (keyword: string) => `/search?keyword=${keyword}`;
-
-  beforeEach(async () => {
-    const module: TestingModule = await Test.createTestingModule({
-      imports: [HttpModule],
-      controllers: [SearchController],
-      providers: [SearchService],
-    }).compile();
-    app = module.createNestApplication();
-    app.useGlobalPipes(new ValidationPipe());
-    await app.init();
-  });
-
-  it('keyword 포함 검색 - GET /search?keyword=coffee', async () => {
-    const keyword = 'coffee';
-    const res = await request(app.getHttpServer()).get(url(keyword));
-    const info: { papers: PaperInfoExtended[] } = JSON.parse(res.text);
-    expect(info.papers.length).toBe(20);
-    // TODO: type check
-    // items.forEach((item) => {
-    //   expect(item).toBeInstanceOf(PaperInfoExtended);
-    // });
-  });
-  it('keyword 미포함시 error - GET /search?keyword=', () => {
-    return request(app.getHttpServer()).get(url('')).expect(400);
-  });
-});
diff --git a/backend/src/util.ts b/backend/src/util.ts
index 247bb9a..9c16960 100644
--- a/backend/src/util.ts
+++ b/backend/src/util.ts
@@ -1,5 +1,5 @@
 const BASE_URL = 'https://api.crossref.org/works';
-export const CROSSREF_API_URL = (keyword: string, rows = 5, selects: string[] = ['author', 'title', 'DOI'], page = 1) =>
+export const CROSSREF_API_URL = (keyword: string, rows = 5, page = 1, selects: string[] = ['author', 'title', 'DOI']) =>
   `${BASE_URL}?query=${keyword}&rows=${rows}&select=${selects.join(',')}&offset=${rows * (page - 1)}`;
 
 export const CROSSREF_API_PAPER_URL = (doi: string) => `${BASE_URL}/${doi}`;