Christophe Ratel Nicolas Halbwachs Pascal Raymond Programming and verifying critical systems by means of the synchronous data-flow language LUSTRE. 112-119 1991 SIGSOFT https://doi.org/10.1145/125083.123062 https://doi.org/10.1145/123041.123062 https://www.wikidata.org/entity/Q111901286 conf/sigsoft/1991 db/conf/sigsoft/sigsoft1991.html#RatelHR91