Murdin, P., M103, in Encyclopedia of Astronomy and Astrophysics, Edited by Paul Murdin, article 6103. Bristol: Institute of Physics Publishing, novembre 2000, DOI:10.1888/0333750888/6103. URL consultato il 9 maggio 2009.
Murdin, P., M103, in Encyclopedia of Astronomy and Astrophysics, Edited by Paul Murdin, article 6103. Bristol: Institute of Physics Publishing, novembre 2000, DOI:10.1888/0333750888/6103. URL consultato il 9 maggio 2009.