Tue Apr 9 17:10 EDT 1996  	Posting of bh20.tar.
Thu Apr 11 14:18:57 EDT 1996	Update. 
Tue Apr 23 10:38:12 EDT 1996	Bug fix, and enhancement.
				(Bug caused crash in certain cases.
				New driver allows manual stepping
				through moves.)	
Fri May 24 13:11:36 EDT 1996	Posting of bh21.tar.
				An additional reducibility check, not
				part of the BH algorithm, has been added.
				See the README file.