diff --git a/sources/Core/CMakeLists.txt b/sources/Core/CMakeLists.txt
index 1138bf5..ee3942a 100644
--- a/sources/Core/CMakeLists.txt
+++ b/sources/Core/CMakeLists.txt
@@ -4,7 +4,6 @@
 
 set(CORE_SRC
     src/Block.cpp
-    src/BlockInformation.cpp
     src/Log.cpp
     src/Parameter.cpp
     src/Parameters.cpp
diff --git a/sources/Core/include/BlockFactory/Core/BlockInformation.h b/sources/Core/include/BlockFactory/Core/BlockInformation.h
index 0de5c4e..dee87ae 100644
--- a/sources/Core/include/BlockFactory/Core/BlockInformation.h
+++ b/sources/Core/include/BlockFactory/Core/BlockInformation.h
@@ -27,8 +27,9 @@ namespace blockfactory {
         using OutputPortsInfo = std::vector<Port::Info>;
         using InputSignalPtr = std::shared_ptr<const blockfactory::core::Signal>;
         using OutputSignalPtr = std::shared_ptr<blockfactory::core::Signal>;
-        // List of possible key for defining block options:
-        extern const std::string BlockOptionPrioritizeOrder;
+
+        // List of possible keys for defining block options:
+        const std::string BlockOptionPrioritizeOrder = "wbt.BlockOptionPrioritizeOrder";
     } // namespace core
 } // namespace blockfactory
 
diff --git a/sources/Core/src/BlockInformation.cpp b/sources/Core/src/BlockInformation.cpp
deleted file mode 100644
index c2cedfd..0000000
--- a/sources/Core/src/BlockInformation.cpp
+++ /dev/null
@@ -1,11 +0,0 @@
-/*
- * Copyright (C) 2018 Istituto Italiano di Tecnologia (IIT)
- * All rights reserved.
- *
- * This software may be modified and distributed under the terms of the
- * GNU Lesser General Public License v2.1 or any later version.
- */
-
-#include "BlockFactory/Core/BlockInformation.h"
-
-const std::string blockfactory::core::BlockOptionPrioritizeOrder = "wbt.BlockOptionPrioritizeOrder";