Huchra, J. P.; Geller, M. J. (June 15, 1982), “Groups of galaxies. I - Nearby groups”, Astrophysical Journal257 (Part 1): 423–437, Bibcode: 1982ApJ...257..423H, doi:10.1086/160000
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Huchra, J. P.; Geller, M. J. (June 15, 1982), “Groups of galaxies. I - Nearby groups”, Astrophysical Journal257 (Part 1): 423–437, Bibcode: 1982ApJ...257..423H, doi:10.1086/160000