Michela Degl'Innocenti Gian Luigi Ferrari Giuliano Pacini Franco Turini RSF: A Formalism for Executable Requirement Specifications. 1235-1246 http://doi.ieeecomputersociety.org/10.1109/32.60312 1990 16 IEEE Trans. Software Eng. 11 db/journals/tse/tse16.html#DeglInnocentiFPT90