Periodic routines have been traditionally identified in Social Sciences as the essential component of social organizations that are persistent in time, with the temporal continuity of such routines constituting the foundation of the preservation of the social systems both between successive generations and between extant and immigrant populations. Open multiagent systems (MAS) with persistent social organizations are, thus, required to be organized around time-persistent periodic routines. In this paper we propose to make use of Coloured Petri Nets (CPN) for the specification of periodic routines that may characterize the social organization of MAS. In particular, the central notions of routine cut, selected routine cut, routine step, and routine step results, as well as the notion of satisfactory performance of a periodic routine, are defined, and illustrated through a detailed example. The notion of routine objective expectation and deviation are used for the analysis of routine performances.