Stephen C. Johnson. On the problem of recognizing zero. In Stanley R. Petrick, Jean E. Sammet, Robert G. Tobey, Joel Moses, editors, Proceedings of the second ACM symposium on Symbolic and algebraic manipulation, SYMSAC 1971, Los Angeles, California, USA, March 23-25, 1971. pages 324-327, ACM, 1971. [doi]
Abstract is missing.