Companions: The Caldwell Objects, ISBN 0-521-82796-5, p 324. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), “A Classification of Globular Clusters”
Astronomical Object Database”. Results for NGC 6397. 2006年11月16日閲覧。 ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), “A Classification of Globular Clusters”
(1999). Villers-Bocage: Through the Lens of the German War Photographer. OldHarlow: Battle of Britain International. ISBN 1-870067-07-X. OCLC 43719285 p
similar finding. ^ Bauer 1997, p. 536. ^ Harlow 1996, p. 1. ^ Bauer 1997, p. 534. ^ Harlow 2006, p. 69. ^ Harlow 2006, p. 79. ^ Williams, H. W. and W. L