B. Perozzi, R. Al-Rfou, and S. Skiena. Proceedings of the 20th ACM SIGKDD international conference on Knowledge discovery and data mining, page 701--710. ACM, (2014)
Y. Yang, and X. Liu. Proceedings of the 22nd annual international ACM SIGIR conference on Research and development in information retrieval, page 42--49. ACM, (1999)