Gray Code and the +- Sign Sequence when +-f (+-f(+-f(...+-f(x)...))) Is Ordered CACM March, 1973 Salzer, H. E. Gray code, sign sequences, ordering, positive monotonic functions, binary system, Galois sum 5.10 CA730306 JB January 24, 1978 10:35 AM 2533 4 2533 2394 5 2533 2533 5 2533 2533 5 2533 2533 5 2533