COLLINDER, Per. On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of Open Galactic Clusters. S.B1-B46. Annals of the Observatory of Lund [online]. 1931 [cit. 2017-09-14]. Čís. 2, s. B1-B46. Dostupné online. Bibcode1931AnLun...2....1C. (anglicky)
SANDERS, W. L. Membership of the open cluster NGC 6913 (M29). S.221. Astronomy and Astrophysics Supplement [online]. Únor 1973 [cit. 2017-09-15]. Roč. 9, s. 221. Dostupné online. Bibcode1973A&AS....9..221S. (anglicky)