King 20

Number of stars per data source

	Reference  385 :  110 stars
	Reference  524 :  648 stars
	Reference  540 :  518 stars

References

 385
Skrutskie M.F., Cutri .M., Weinberg M.D., Schneider S., Carpenter J.M., et al.
(2006) Astron. J. 131, 1163
The Two Micron All Sky Survey (2MASS)
2006AJ....131.1163S
 524
Zacharias N., Monet D.G., Levine S.E., Urban S.E., Gaume R., Wycoff G.L.
(2005) The Naval Observatory
The Naval Observatory Merged Astrometric Dataset (NOMAD)
 540
Glushkova E.V., Zabolotskikh M.V., Koposov S.E., Spiridonova O.I., Vlasyuk V.V., Rastorguev A.S.
(2010) Astron. Lett. 36, 14
Photometry of the poorly studied galactic open star clusters King 13, King 18, King 19, King 20, NGC 136, and NGC 7245
2010AstL...36...14G