Are use case and class diagrams complementary in requirements analysis? An experimental study on use case and class diagrams in UML. - Keng Siau; Lihyunn Lee (Requir. Eng., 2004)

Theoretical vs. Practical Complexity: The Case of UML. - Keng Siau; John Erickson; Lihyunn Lee (J. Database Manag., 2005)