Isotopica: a tool for the calculation and viewing of complex isotopic envelopes. - Jorge Fernandez-de-Cossío; Luis Javier González; Yoshinori Satomi; Lazaro Betancourt; Yassel Ramos; Vivian Huerta; Abel Amaro; Vladimir Besada; Gabriel Padron; Naoto Minamino; Toshifumi Takao (Nucleic Acids Res., 2004)