James G. Nourse Specification and unconstrained enumeration of conformations of chemical structures for computer-assisted structure elucidation. 168-172 1981 21 Journal of Chemical Information and Computer Sciences 3 http://pubs.acs.org/cgi-bin/archive.cgi/jcisd8/1981/21/i03/f-pdf/f_ci00031a012.pdf db/journals/jcisd/jcisd21.html#Nourse81