Sanner, J.; Geffert, M.; Brunzendorf, J.; Schmoll, J. (1999). «Photometric and kinematic studies of open star clusters. I. NGC 581 (M 103)». Astronomy and Astrophysics. 349: 448–456. Bibcode:1999A&A...349..448S. arXiv:astro-ph/9908059.
harvard.edu
adsabs.harvard.edu
Sanner, J.; Geffert, M.; Brunzendorf, J.; Schmoll, J. (1999). «Photometric and kinematic studies of open star clusters. I. NGC 581 (M 103)». Astronomy and Astrophysics. 349: 448–456. Bibcode:1999A&A...349..448S. arXiv:astro-ph/9908059.
ttgnet.com
Robert Bruce Thompson [1], M103 (open cluster in Cassiopeia).