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