N. Holloway, S. Ravindran, и A. Gibbons. Graph-Theoretic Concepts in Computer Science, том 790 из Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (1994)
E. Anshelevich, и A. Karagiozova. Proceedings of the thirty-ninth annual ACM symposium on Theory of computing, стр. 391--400. New York, NY, USA, ACM, (2007)