^ abcFeretti, L.; Giovannini, G. (February 1988). "NGC 6047 - Radio source interaction with the environment". Astronomy and Astrophysics. 191: 21. Bibcode:1988A&A...191...21F. ISSN0004-6361.
^ abcLiuzzo, E.; Giovannini, G.; Giroletti, M. (March 2011). "Nuclear properties of Brightest Cluster Galaxies: results and new observations for two peculiar cases". arXiv:1103.0450 [astro-ph.CO].
^ abHeckman, T. M.; Smith, Eric P.; Baum, Stefi A.; van Breugel, W. J. M.; Miley, G. K.; Illingworth, G. D.; Bothun, G. D.; Balick, B. (December 15, 1986). "Galaxy collisions and mergers - The genesis of very powerful radio sources?". The Astrophysical Journal. 311: 526–547. Bibcode:1986ApJ...311..526H. doi:10.1086/164793. ISSN0004-637X.