# ** BVD 21
**Wikidata**: [Q87372970](https://www.wikidata.org/wiki/Q87372970)  
**Source**: https://4ort.xyz/entity/-bvd-21


## References

1. SIMBAD
2. Astrophysical and Dynamical study of New Wide Common Proper Motion Binaries
3. The Tycho-2 catalogue of the 2.5 million brightest stars
4. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
5. Gaia Data Release 2
6. The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog