H. Jerjen et A. Dressler, « Studies of the Centaurus cluster. I. A catalogue of galaxies in the central region of the Centaurus cluster », Astronomy and Astrophysics Supplement series, vol. 124, , p. 1-12 (DOI10.1051/aas:1997355, lire en ligne [PDF])
Gene G. Byrd, Tarsh Freeman, Sethanne Howard et Ronald J. Buta, « The Ringed Spiral Galaxy NGC4622. II. An Independent Determination that the Two Outer Arms Lead », The Astronomical Journal, vol. 135, no 1, , p. 408-413 (DOI10.1088/0004-6256/135/1/408, Bibcode2008AJ....135..408B, lire en ligne [PDF])
H. Jerjen et A. Dressler, « Studies of the Centaurus cluster. I. A catalogue of galaxies in the central region of the Centaurus cluster », Astronomy and Astrophysics Supplement series, vol. 124, , p. 1-12 (DOI10.1051/aas:1997355, lire en ligne [PDF])
Gene G. Byrd, Tarsh Freeman, Sethanne Howard et Ronald J. Buta, « The Ringed Spiral Galaxy NGC4622. II. An Independent Determination that the Two Outer Arms Lead », The Astronomical Journal, vol. 135, no 1, , p. 408-413 (DOI10.1088/0004-6256/135/1/408, Bibcode2008AJ....135..408B, lire en ligne [PDF])
A.M. Garcia, « General study of group membership. II -Determination of nearby groups », Astronomy and Astrophysics Supplement Series, vol. 100 #1, , p. 47-90 (Bibcode1993A&AS..100...47G, lire en ligne)|format=PDF
A.M. Garcia, « General study of group membership. II -Determination of nearby groups », Astronomy and Astrophysics Supplement Series, vol. 100 #1, , p. 47-90 (Bibcode1993A&AS..100...47G, lire en ligne)|format=PDF
Gene G. Byrd, Tarsh Freeman, Sethanne Howard et Ronald J. Buta, « The Ringed Spiral Galaxy NGC4622. II. An Independent Determination that the Two Outer Arms Lead », The Astronomical Journal, vol. 135, no 1, , p. 408-413 (DOI10.1088/0004-6256/135/1/408, Bibcode2008AJ....135..408B, lire en ligne [PDF])