Digging into Use Case Relationships. - Gonzalo Génova; Juan Lloréns; Víctor Quintana (UML, 2002)

Errors in the UML metamodel? - José Miguel Fuentes; Víctor Quintana; Juan Lloréns; Gonzalo Génova; Rubén Prieto-Díaz (ACM SIGSOFT Softw. Eng. Notes, 2003)