NGC 6520

Number of stars per data source

	Reference  999 :    2 stars

References

 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