The Roles of ``Roles'' in Use Case Diagrams.

Alain Wegmann Guy Genilloud The Roles of ``Roles'' in Use Case Diagrams. 210-224 http://link.springer.de/link/service/series/0558/bibs/1939/19390210.htm 2000 conf/uml/2000 UML db/conf/uml/uml2000.html#WegmannG00