1. Abbott, D. C. (1979). In P. S. Conti & C. W. H. de Loore (Eds.), IAU Symposium 83, Mass Loss and the Evolution of O Type Stars (p. 237). Dordrecht: Reidel.
2. Abbott, D. C. (1982). Astrophysical Journal, 259, 282.
3. Alcock, C., & Illarionov, A. (1980). Astrophysical Journal, 235, 541.
4. Alecian, G. (1996). Astronomy & Astrophysics, 310, 872.
5. Babel, J. (1995). Astronomy & Astrophysics, 301, 823.