Berkeley 20
Number of stars per data source
Reference 95 : 428 stars
Reference 275 : 276 stars
References
- 95
- MacMinn D., Phelps R.L., Janes K.A., Friel E.
- (1994) Astron. J. 107, 1806
- Berkeley 20: an unusual old open cluster
- 1994AJ....107.1806M
- 275
- Durgapal A.K., Pandey A.K., Mohan V.
- (2001) Astron. Astrophys. 372, 71
- Multicolour CCD photometry of old open clusters: King 5 and Be 20
- 2001A&A...372...71D