Y. Cheung, H. Scheepers, M. Swift, V. Lee, and J. Bal. PRO-VE, volume 336 of IFIP Advances in Information and Communication Technology, page 380-387. Springer, (2010)
M. Nguyen, S. Hui, and A. Fong. Australasian Conference on Artificial Intelligence, volume 7106 of Lecture Notes in Computer Science, page 717-726. Springer, (2011)