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Thomas H. Jarrett, John M. Carpenter, John E. Gizis, Carol Lonsdaleová, John Huchra, Thomas Jay Chester, David G. Monet, J. Davy Kirkpatrick, Kenneth A. Marsh, Roc M. Cutri: The Two Micron All Sky Survey (2MASS). In: The Astronomical Journal. únor 2006. DOI10.1086/498708.
LY, C.; WALKER, R. C.; WROBEL, J. M. An Attempt to Probe the Radio Jet Collimation Regions in NGC 4278, NGC 4374 (M84), and NGC 6166. S.119–124. Astronomical Journal [online]. Leden 2004 [cit. 2018-04-18]. Roč. 127, s. 119–124. Dostupné online. doi:10.1086/379855. Bibcode2004AJ....127..119L. (anglicky)