Turner, T. J.; George, I. M.; Nandra, K.; Mushotzky, R. F. (November 1997). "ASCA Observations of Type 2 Seyfert Galaxies. I. Data Analysis Results". The Astrophysical Journal Supplement Series. 113 (1): 23–67. arXiv:astro-ph/9608170. Bibcode:1997ApJS..113...23T. doi:10.1086/313053.
Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D. (1 April 2012). "The Link Between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies". The Astrophysical Journal. 748 (2): 130. arXiv:1201.5397. Bibcode:2012ApJ...748..130M. doi:10.1088/0004-637X/748/2/130.
Turner, T. J.; George, I. M.; Nandra, K.; Mushotzky, R. F. (November 1997). "ASCA Observations of Type 2 Seyfert Galaxies. I. Data Analysis Results". The Astrophysical Journal Supplement Series. 113 (1): 23–67. arXiv:astro-ph/9608170. Bibcode:1997ApJS..113...23T. doi:10.1086/313053.
Rubin, V. C. (August 1974). "Two chains of interesting southern galaxies : NGC 7172-7173-7174-7176and NGC 7201-7203-7204". The Astrophysical Journal. 191: 645. Bibcode:1974ApJ...191..645R. doi:10.1086/153005.
Marshall, F. E.; Boldt, E. A.; Holt, S. S.; Mushotzky, R. F.; Rothschild, R. E.; Serlemitsos, P. J.; Pravdo, S. H. (July 1979). "New hard X-ray sources observed with HEAO A-2". The Astrophysical Journal Supplement Series. 40: 657. Bibcode:1979ApJS...40..657M. doi:10.1086/190600.
Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D. (1 April 2012). "The Link Between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies". The Astrophysical Journal. 748 (2): 130. arXiv:1201.5397. Bibcode:2012ApJ...748..130M. doi:10.1088/0004-637X/748/2/130.
Turner, T. J.; George, I. M.; Nandra, K.; Mushotzky, R. F. (November 1997). "ASCA Observations of Type 2 Seyfert Galaxies. I. Data Analysis Results". The Astrophysical Journal Supplement Series. 113 (1): 23–67. arXiv:astro-ph/9608170. Bibcode:1997ApJS..113...23T. doi:10.1086/313053.
Rubin, V. C. (August 1974). "Two chains of interesting southern galaxies : NGC 7172-7173-7174-7176and NGC 7201-7203-7204". The Astrophysical Journal. 191: 645. Bibcode:1974ApJ...191..645R. doi:10.1086/153005.
Marshall, F. E.; Boldt, E. A.; Holt, S. S.; Mushotzky, R. F.; Rothschild, R. E.; Serlemitsos, P. J.; Pravdo, S. H. (July 1979). "New hard X-ray sources observed with HEAO A-2". The Astrophysical Journal Supplement Series. 40: 657. Bibcode:1979ApJS...40..657M. doi:10.1086/190600.
Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D. (1 April 2012). "The Link Between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies". The Astrophysical Journal. 748 (2): 130. arXiv:1201.5397. Bibcode:2012ApJ...748..130M. doi:10.1088/0004-637X/748/2/130.