Hanson, M. M.; Howarth, I.D.; Conti, P.S. The Young Massive Stellar Objects of M17. The Astrophysical Journal. 1997, 489 (2): 698–718. Bibcode:1997ApJ...489..698H. doi:10.1086/304808.
Hanson, M. M.; Howarth, I.D.; Conti, P.S. The Young Massive Stellar Objects of M17. The Astrophysical Journal. 1997, 489 (2): 698–718. Bibcode:1997ApJ...489..698H. doi:10.1086/304808.