Abstract. A pattern-based approach to the presentation, codification and reuse of property specifications for finite-state verification was proposed by Dwyer and his colleagues in [4,3]. The patterns enable nonexperts to read and write formal specifications for realistic systems and facilitate easy conversion of specifications between formalisms, such as LTL, CTL, QRE. In this paper we extend the pattern system with events — changes of values of variables in the context of LTL. 1