Ronald J. Buta, Gene G. Byrd, Tarsh Freeman The Ringed Spiral Galaxy NGC 4622. I. Photometry, Kinematics, and the Case for Two Strong Leading Outer Spiral Arms // Astronomical Journal. — 2003. — DOI:10.1086/345821 — arΧiv:0211002
Ronald J. Buta, Gene G. Byrd, Tarsh Freeman The Ringed Spiral Galaxy NGC 4622. I. Photometry, Kinematics, and the Case for Two Strong Leading Outer Spiral Arms // Astronomical Journal. — 2003. — DOI:10.1086/345821 — arΧiv:0211002