A quantitative study of O stars in NGC 2244 and the Monoceros OB2 association, Martins, F.; Mahy, L.; Hillier, D. J.; Rauw, G., Astronomy and Astrophysics538, pp. A39, Bibcode: 2012A&A...538A..39M, doi:10.1051/0004-6361/201117458.
A quantitative study of O stars in NGC 2244 and the Monoceros OB2 association, Martins, F.; Mahy, L.; Hillier, D. J.; Rauw, G., Astronomy and Astrophysics538, pp. A39, Bibcode: 2012A&A...538A..39M, doi:10.1051/0004-6361/201117458.