Robert J. K. Jacob Leonidas Deligiannidis Stephen Morrison A Software Model and Specification Language for Non-WIMP User Interfaces. 1-46 1999 6 ACM Trans. Comput.-Hum. Interact. 1 http://doi.acm.org/10.1145/310641.310642 db/journals/tochi/tochi6.html#JacobDM99