&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Bulletin of Mathematical Biology. 1974.<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Vol. 36 No. 5/6 : Vol. 36 No. 5/6. &mdash; 1974. &mdash; ISSN 0092-8240.<br><br><br><br>[ SYS NUM: 15406 ]