Roberto Barbuti Andrea Maggiolo-Schettini Paolo Milazzo Angelo Troina Bisimulation Congruences in the Calculus of Looping Sequences. 93-107 2006 conf/ictac/2006 ICTAC http://dx.doi.org/10.1007/11921240_7 db/conf/ictac/ictac2006.html#BarbutiMMT06