\input zb-basic \input zb-ioport \iteman{io-port 06059130} \itemau{Valero, Valent{\'\i}n; Maci\`a, Hermenegilda; Pardo, Juan Jos\'e; Cambronero, Mar{\'\i}a Emilia; D{\'\i}az, Gregorio} \itemti{Transforming web services choreographies with priorities and time constraints into prioritized-time colored Petri nets.} \itemso{Sci. Comput. Program. 77, No. 3, 290-313 (2012).} \itemab Summary: A Web Service is a self-describing, self-contained modular application that can be published, located, and invoked over a network, such as the Internet. Web Service composition provides a way to obtain value-added services by combining different existing facilities, which are then able to support the integration of commercial applications. WS-CDL (web services choreography description language) is a W3C candidate recommendation for the description of peer-to-peer collaborations by participants in a web services composition. This paper focuses on several important aspects of WS-CDL, namely, data variables, timed restrictions, as well as the priorization of collaborations. In WS-CDL there are no priorities, thus, one of our first goals is to provide a WS-CDL definition of prioritized collaborations. We also define a semantics of WS-CDL (with priorities) by means of prioritized-timed colored Petri nets. \itemrv{~} \itemcc{} \itemut{web services; web service composition; priorities; choreography; timed colored Petri nets} \itemli{doi:10.1016/j.scico.2011.05.002} \end