Berkeley 9

Number of stars per data source

	Reference  495 :  486 stars
	Reference  541 :  782 stars
	Reference  548 : 1310 stars

495: Maciejewski G., Niedzielski A.; (2007) Astron. Astrophys. 467, 1065; CCD BV survey of 42 open clusters; 2007A&A...467.1065M
541: Lata S., Pandey A.K., Kumar B., Bhatt H., Pace G., Sharma S.; (2010) Astron. J. 139, 378; A Deep UBVRI CCD Photometry of Six Open Star Clusters in the Galactic Anticenter Region; 2010AJ....139..378L
548: Subramaniam A., Carraro G., Janes K.A; (2010) Mon. Not. R. Astron. Soc. 404, 1385; Optical photometry and basic parameters of 10 unstudied open clusters; 2010MNRAS.404.1385S