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Abraham Mahtessian, « Groups of galaxies. III. Some empirical characteristics », Astrophysics, vol. 41 #3, , p. 308-321 (DOI10.1007/BF03036100, lire en ligne, consulté le )
Devendra Sahu, Sheo Kumar Pandey, D. K. Chakraborty, Viswanathan Mohan et Ajit Kembhavi, « Nuclear dust and outer shells in the elliptical galaxy NGC 7562 », Astronomy and Astrophysics, vol. 314, , p. 721-728 (Bibcode1996A&A...314..721S, lire en ligne [html] 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)
Lorenza Levy, James A. Rose, Jacqueline H. van Gorkom et Brian Chaboyer, « The Effect of Cluster Environment on Galaxy Evolution in the Pegasus I Cluster », The Astronomical Journal, vol. 133, no 3, , p. 1104 (DOI10.1086/510723, Bibcode2007AJ....133.1104L, lire en ligne [PDF])
Devendra Sahu, Sheo Kumar Pandey, D. K. Chakraborty, Viswanathan Mohan et Ajit Kembhavi, « Nuclear dust and outer shells in the elliptical galaxy NGC 7562 », Astronomy and Astrophysics, vol. 314, , p. 721-728 (Bibcode1996A&A...314..721S, lire en ligne [html] PDF)
Lorenza Levy, James A. Rose, Jacqueline H. van Gorkom et Brian Chaboyer, « The Effect of Cluster Environment on Galaxy Evolution in the Pegasus I Cluster », The Astronomical Journal, vol. 133, no 3, , p. 1104 (DOI10.1086/510723, Bibcode2007AJ....133.1104L, lire en ligne [PDF])
researchgate.net
Abraham Mahtessian, « Groups of galaxies. III. Some empirical characteristics », Astrophysics, vol. 41 #3, , p. 308-321 (DOI10.1007/BF03036100, lire en ligne, consulté le )