Alexander Borgida Sol J. Greenspan John Mylopoulos Knowledge Reperesentation as the Basis for Requirements Specification (Reprint). 152-169 1985 conf/wi/1985 Wissensbasierte Systeme db/conf/wi/wi1985.html#BorgidaGM85 https://doi.org/10.1007/978-3-642-70840-4_13