Lang, W. J.; Masheder, M. R. W.; Dame, T. M.; Thaddeus, P. (May 2000). "The lambda -Orionis Ring in CO". Astronomy & Astrophysics. 357: 1001–1012. Bibcode:2000A&A...357.1001L. ISSN0004-6361.
Lang, W. J.; Masheder, M. R. W.; Dame, T. M.; Thaddeus, P. (May 2000). "The lambda -Orionis Ring in CO". Astronomy & Astrophysics. 357: 1001–1012. Bibcode:2000A&A...357.1001L. ISSN0004-6361.