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. 2019-03-05]. Čís. 2, s. B1-B46. Dostupné online. Bibcode1931AnLun...2....1C. (anglicky)
MELOTTE, P. J. A Catalogue of Star Clusters shown on Franklin-Adams Chart Plates. S. 175. Memoirs of the Royal Astronomical Society [online]. 1915 [cit. 20119-02-26]. Roč. 60, s. 175. Dostupné online. Bibcode1915MmRAS..60..175M. (anglicky)
CARRARO, G.; CHIOSI, C. Galactic orbits of the old open clusters NGC 188, NGC 2682, NGC 2420, NGC 752 and NGC 2506. S. 751–758. Astronomy and Astrophysics [online]. Srpen 1994 [cit. 2019-03-05]. Roč. 288, s. 751–758. Dostupné online. Bibcode1994A&A...288..751C. (anglicky)
u-strasbg.fr
simbad.u-strasbg.fr
SIMBAD Astronomical Database: Results for NGC 2506 [online]. [cit. 2019-03-05]. Dostupné online. (anglicky)
univie.ac.at
WEBDA page for open cluster NGC 2506 [online]. [cit. 2019-03-05]. Dostupné online. (anglicky)
web.archive.org
FROMMERT, Hartmut. Revised NGC Data for NGC 2506 [online]. SEDS.org [cit. 2019-03-05]. Dostupné v archivu pořízeném dne 2012-04-23. (anglicky)