Gian Luigi Ferrari Ugo Montanari Paola Quaglia A Pi-Calculus with Explicit Substitutions. 53-103 1996 168 Theor. Comput. Sci. 1 db/journals/tcs/tcs168.html#FerrariMQ96 http://dx.doi.org/10.1016/S0304-3975(96)00063-1