Jifeng He 0001 C. A. R. Hoare Martin Fränzle Markus Müller-Olm Ernst-Rüdiger Olderog Michael Schenke Michael R. Hansen Anders P. Ravn Hans Rischel Provably Correct Systems. 288-335 1994 conf/ftrtft/1994 FTRTFT db/conf/ftrtft/ftrtft1994.html#JifengHFMOSHRR94 https://doi.org/10.1007/3-540-58468-4_171