GARCIA, A. General study of group membership. II - Determination of nearby groups. S. 47–90. Astronomy and Astrophysics Supplement [online]. Červenec 1993 [cit. 2018-02-23]. Roč. 100, s. 47–90. Dostupné online. Bibcode1993A&AS..100...47G. (anglicky)
GIURICIN, Giuliano; MARINONI, Christian; CERIANI, Lorenzo, et al. Nearby Optical Galaxies: Selection of the Sample and Identification of Groups. S. 178–194. Astrophysical Journal [online]. Listopad 2000 [cit. 2018-02-23]. Roč. 543, čís. 1, s. 178–194. Dostupné online. arXivastro-ph/0001140. DOI10.1086/317070. Bibcode2000ApJ...543..178G. (anglicky)