Originally from [Anderson and Belnap, 1962, p31-32]
[Hughes and Cresswell, 1968, p295]
My thanks to Dolph Ulrich [Ulrich, email, 2005] for straightening me out and documenting that the two C4's that used to be on this page were the same system.
© Copyright 2006, by John Halleck, All Rights Reserved.
This page is http://www.cc.utah.edu/~nahaj/logic/structures/systems/c4.html
This page was last modified on July 17, 2006