P. Kelsen, Q. Ma, и C. Glodt. Fundamental Approaches to Software Engineering, том 6603 из Lecture Notes in Computer Science, стр. 171--185. Springer, (2011)
I. Jureta, S. Faulkner, и P. Schobbens. RE '06: Proceedings of the 14th IEEE International Requirements Engineering Conference (RE'06), стр. 116--125. Washington, DC, USA, IEEE Computer Society, (2006)