The perihelion dates in the past appearances are printed on Catalog of Cometary Orbits 1996.
The perihelion dates of non-observed returns in 1940 and 1961 are calculated using the Minor Planet & Comet Ephemeris Service.
The perihelion date of non-observed return in 1982 is published on M.P.E.C. 2012-J16.
Copyright(C) Seiichi Yoshida (comet@aerith.net). All rights reserved.