Rüdiger Walentowski Unique, Unambiguous Representation of Chemical Structures by Computerization of a Simple Notation. 181-192 1980 20 Journal of Chemical Information and Computer Sciences 3 http://pubs.acs.org/cgi-bin/archive.cgi/jcisd8/1980/20/i03/f-pdf/f_ci60023a015.pdf db/journals/jcisd/jcisd20.html#Walentowski80