Hermenegilda Macià Valentín Valero Ruiz Fernando Cuartero David de Frutos-Escrig A congruence relation for sPBC. 85-128 2008 32 Formal Methods in System Design 2 http://dx.doi.org/10.1007/s10703-007-0045-2 db/journals/fmsd/fmsd32.html#MaciaRCF08