A weakest precondition semantics for communicating processes - Elrad, Tzilla; Francez, Nissim (haṭ- Ṭeḵniyyôn, Māḵôn Ṭeḵnôlôgî le-Yiśrā'ēl <Ḥêfā> / Department of Computer Science: Technical report, 1982)