The perihelion dates in the past appearances are printed on Catalog of Cometary Orbits 1996.
The perihelion dates of non-observed returns from 1908 to 1987 are calculated using the Minor Planet & Comet Ephemeris Service.
The perihelion dates of non-observed returns from 1890 to 1899 are calculated by Kazuo Kinoshita (http://www9.ocn.ne.jp/~comet/pcmtn/0072p.htm).
Copyright(C) 1995-2008 Seiichi Yoshida (comet@aerith.net). All rights reserved.