NGC 6639

Number of stars per data source

	Reference 1029 :    2 stars

References

 1029
Kharchenko N.V., Piskunov A.E., Röser S., Schilbach E., Scholz R.-D.
(2005) Astron. Astrophys. 438, 1163
Astrophysical parameters of galactic open clusters
2005A&A...438.1163K