Robert M. Mulligan Mary Dieli Jakob Nielsen Steven E. Poltrock Daniel Rosenberg Susan Erlich Rudman Designing Usable Systems Under Real-World Constraints: A Practitioners Forum. 149-152 1992 conf/chi/1992 CHI http://doi.acm.org/10.1145/142750.142777 db/conf/chi/chi92.html#MulliganDNPRR92