NGC 581

Number of stars per data source

	Reference   32 :    1 star
	Reference   84 :    2 stars

32: Lee T.A.; (1970) Astrophys. J. 162, 217; Photometry of High-luminosity M-type Stars; 1970ApJ...162..217L
84: Echevarria J., Roth M., Warman J.; (1979) Rev. Mex. Astron. Astrofis. 4, 287; Photometric Study of Trapezium-type Systems; 1979RMxAA...4..287E