Newell, M. E.; Newell, R. G.; Sancha, T. L. (1972). "A solution to the hidden surface problem". Proceedings of the ACM annual conference on – ACM'72. Vol. 1. p. 443. doi:10.1145/800193.569954. S2CID13829930.
Newell, M. E.; Newell, R. G.; Sancha, T. L. (1972). "A solution to the hidden surface problem". Proceedings of the ACM annual conference on – ACM'72. Vol. 1. p. 443. doi:10.1145/800193.569954. S2CID13829930.