Keel idr. (1985). Keel, W. C.; Kennicutt, R. C., mlajši; Hummel, E.; Hulst, J. M. van der (1. maj 1985), »The effects of interactions on spiral galaxies. I. Nuclear activity and star formation.«, The Astronomical Journal, 90: 708–730, Bibcode:1985AJ.....90..708K, doi:10.1086/113779, ISSN0004-6256
Keel idr. (1985). Keel, W. C.; Kennicutt, R. C., mlajši; Hummel, E.; Hulst, J. M. van der (1. maj 1985), »The effects of interactions on spiral galaxies. I. Nuclear activity and star formation.«, The Astronomical Journal, 90: 708–730, Bibcode:1985AJ.....90..708K, doi:10.1086/113779, ISSN0004-6256
Keel idr. (1985). Keel, W. C.; Kennicutt, R. C., mlajši; Hummel, E.; Hulst, J. M. van der (1. maj 1985), »The effects of interactions on spiral galaxies. I. Nuclear activity and star formation.«, The Astronomical Journal, 90: 708–730, Bibcode:1985AJ.....90..708K, doi:10.1086/113779, ISSN0004-6256