Daniel Sinnig Maik Wurdel Peter Forbrig Patrice Chalin Ferhat Khendek Practical Extensions for Task Models. 42-55 2007 conf/tamodia/2007 TAMODIA http://dx.doi.org/10.1007/978-3-540-77222-4_5 db/conf/tamodia/tamodia2007.html#SinnigWFCK07