Gilli, R.; et al. (March 2000). "The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN". Astronomy and Astrophysics. 355: 485–498. arXiv:astro-ph/0001107. Bibcode:2000A&A...355..485G.
Gilli, R.; et al. (March 2000). "The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN". Astronomy and Astrophysics. 355: 485–498. arXiv:astro-ph/0001107. Bibcode:2000A&A...355..485G.