P. Chapman, G. Stapleton, J. Howse, and I. Oliver. 2011 IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC), page 87-94. (September 2011)
Y. Liang, S. Ke, J. Zhang, X. Yi, and Y. Zheng. Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence, International Joint Conferences on Artificial Intelligence Organization, (July 2018)