J. Park, Y. Park, J. Kim, J. Cha, S. Kim, and A. Oh. Proceedings of the Fifth Annual ACM Conference on Learning at Scale, page 58:1--58:10. New York, NY, USA, ACM, (2018)
M. Gao, W. Xie, C. Lu, and R. Shen. The 3rd International Conference on Internet Multimedia Computing and Service (ICIMCS2011), Chengdu, China, ACM, (August 2011)