D. Citron, and P. Ginsparg. (2014)cite arxiv:1412.2716Comment: 6 pages, plus 10 pages of supplementary material. To appear in PNAS (online 8 Dec 2014).
T. Bell, P. Curzon, Q. Cutts, V. Dagiene, and B. Haberman. Proceedings of the 16th annual joint conference on Innovation and technology in computer science education, page 391--391. New York, NY, ACM, (2011)
C. Daskalakis, P. Goldberg, and C. Papadimitriou. STOC '06: Proceedings of the thirty-eighth annual ACM symposium on Theory of computing, page 71--78. New York, NY, USA, ACM, (2006)