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NGC 21 (English Wikipedia)

Analysis of information sources in references of the Wikipedia article "NGC 21" in English language version.

refsWebsite
Global rank English rank
2caltech.edu
887th place
714th place
1in-the-sky.org
low place
low place
1harvard.edu
18th place
17th place

caltech.edu

nedipac.caltech.edu

  • "NASA/IPAC Extragalactic Database". Results for NGC 0021. Retrieved 2010-05-03.
  • "Distance Results for NGC 0021". NASA/IPAC Extragalactic Database. Retrieved 2010-05-03.

harvard.edu

ui.adsabs.harvard.edu

  • Garcia, A. M. (1993). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47. Bibcode:1993A&AS..100...47G.

in-the-sky.org