NGC 2251

Number of stars per data source

	Reference   97 :    1 star
	Reference  206 :    1 star
	Reference  389 :    2 stars

References

 97

Young A., Martin A.E.

(1973) Astrophys. J. 181, 805

A search for Ap stars in open clusters

1973ApJ...181..805Y

 206

Hiltner W.A.

(1956) Astrophys. J. Suppl. 2, 389

Photometric, polarization and spectrographic observations of O and B stars

1956ApJS....2..389H

 389

van Rensbergen W., Hammerschlag G., van den Heuvel E.P.J

(1978) Astron. Astrophys. 64, 131

Spectroscopic studies of open clusters - A search for Ap stars

1978A&A....64..131V