J. Aspnes, K. Chang, and A. Yampolskiy. Proceedings of the Sixteenth Annual ACM-SIAM Symposium on Discrete Algorithms, page 43–52. USA, Society for Industrial and Applied Mathematics, (2005)
X. He, and D. Kempe. Proceedings of the 22nd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 885–894. New York, NY, USA, Association for Computing Machinery, (2016)