NGC 663

Number of stars per data source

	Reference   15 :    1 star
	Reference   30 :    2 stars
	Reference   58 :   18 stars

15: Slettebak A.; (1968) Astrophys. J. 154, 933; Stellar rotation and be stars in the h and Chi Persei association; 1968ApJ...154..933S
30: Meadows A. J.; (1961) Monthly Notices Roy. Astron. Soc. 123, 81; Turbulence and rotation in early-type stars; 1961MNRAS.123...81M
58: Slettebak A.; (1985) Astrophys. J. Suppl. 59, 769; Be stars in open clusters; 1985ApJS...59..769S