Berkeley 31

Number of stars per data source

	Reference   60 :  699 stars
	Reference   88 : 1933 stars
	Reference  389 :  193 stars

References

 60

Guetter H.H.

(1993) Astron. J. 106, 220

Photometric study of the old galactic cluster Be31

1993AJ....106..220G

 88

Phelps R.L., Janes K.A., Montgomery K.A.

(1994) Astron. J. 107, 1079

Development of the galactic disk: a search for the oldest open clusters

1994AJ....107.1079P

 389

Hasegawa T., Malasan H.L., Kawakita H., Obayashi H., Kurabayashi T., Nakai T., Hyakkai M., Arimoto N.

(2004) Publ. Astron. Soc. Japan 56, 295

New photometric data of old open clusters in the anti-galactic center region

2004PASJ...56..295H