Collinder 121

Number of stars per data source

	Reference   11 :    1 star
	Reference   83 :   13 stars
	Reference  213 :    1 star
	Reference  478 :    1 star
	Reference  825 :    1 star
	Reference  999 :   26 stars

References

 11
Morgan W.W., Roman N.G.
(1950) Astrophys. J. 112, 362
Revised standards for supergiants on the system of the Yerkes Spectral Atlas
1950ApJ...112..362M
 83
Hiltner W.A., Garrison R.F., Schild R.E.
(1969) Astrophys. J. 157, 313
MK spectral types for bright southern OB stars
1969ApJ...157..313H
 213
Garrison R.F., Hiltner W.A., Schild R.E.
(1977) Astrophys. J. Suppl. 35, 111
MK spectral classifications for southern OB stars
1977ApJS...35..111G
 478
Buscombe W.
(1969) Mon. Not. R. Astr. Soc. 144, 31
Line strengths for southern OB stars - II
1969MNRAS.144...31B
 825
Woods M.L.
(1958) Mem. Commonwealth Obs. Mount Stromlo 16, 125
Spectral types of bright southern stars
 999
Houk N., Cowley A.P., Smith-Moore M.
University of Michigan (Ann Arbor) Vol 1 (1975), Vol 2 (1978), Vol 3 (1982), Vol 4 (1988), Vol 5 (1999)
The University of Michigan Catalogue of two-dimensional Spectral Types for the HD stars
1975mctd.book.....H