M. Petre, and A. Blackwell. VLHCC '07: Proceedings of the IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC 2007), page 239--242. Washington, DC, USA, IEEE Computer Society, (2007)
L. Osterweil. ESEC/FSE-11: Proceedings of the 9th European software engineering conference held jointly with 11th ACM SIGSOFT international symposium on Foundations of software engineering, page 6--14. New York, NY, USA, ACM, (2003)