When you use psi-ms.obo, please cite the following publication:
Mayer G, Montecchi-Palazzi L, Ovelleiro D, Jones AR, Binz PA, Deutsch EW, Chambers M, Kallhardt M, Levander F, Shofstahl J, Orchard S, Vizcaíno JA, Hermjakob H, Stephan C, Meyer HE, Eisenacher M; HUPO-PSI Group. The HUPO proteomics standards initiative- mass spectrometry controlled vocabulary. Database (Oxford). 2013 Mar 12;2013:bat009. doi: 10.1093/database/bat009. Print 2013. pdf