J. Dutta, C. Chowdhury, S. Roy, A. Middya, and F. Gazi. Proceedings of the 18th International Conference on Distributed Computing and Networking, page 42:1--42:6. New York, NY, USA, ACM, (2017)
R. Thurik. The sources of entrepreneurial activity: Advances in the study of entrepreneurship, innovation, and economic growth(11), JAI Press, Stanford, CT, (1999)