Reichard, T.A.; Heckman, T.M. (januar 2009). „The Lopsidedness of Present-Day Galaxies: Connections to the Formation of Stars, the Chemical Evolution of Galaxies, and the Growth of Black Holes”. The Astrophysical Journal. 691 (2): 1005—1020. arXiv:0809.3310. doi:10.1088/0004-637X/691/2/1005.
Reichard, T.A.; Heckman, T.M. (januar 2009). „The Lopsidedness of Present-Day Galaxies: Connections to the Formation of Stars, the Chemical Evolution of Galaxies, and the Growth of Black Holes”. The Astrophysical Journal. 691 (2): 1005—1020. arXiv:0809.3310. doi:10.1088/0004-637X/691/2/1005.