MODi : a powerful and convenient web server for identifying multiple post-translational peptide modifications from tandem mass spectra. - Sangtae Kim; Seungjin Na; Ji Woong Sim; Heejin Park; Jaeho Jeong; Hokeun Kim; Younghwan Seo; Jawon Seo; Kong-Joo Lee; Eunok Paek (Nucleic Acids Res., 2006)