J. Ratzinger, T. Sigmund, and H. Gall. MSR '08: Proceedings of the 2008 international workshop on Mining software repositories, page 35--38. New York, USA, ACM, (2008)
C. Marlow, M. Naaman, D. Boyd, and M. Davis. HYPERTEXT '06: Proceedings of the seventeenth conference on Hypertext and hypermedia, page 31--40. New York, NY, USA, ACM Press, (2006)