Jonathan Billington Amar Kumar Gupta Guy Edward Gallasch Modelling and Analysing the Contract Net Protocol - Extension Using Coloured Petri Nets. 169-184 2008 FORTE http://dx.doi.org/10.1007/978-3-540-68855-6_11 conf/forte/2008 db/conf/forte/forte2008.html#BillingtonGG08