The Dense Ring in the Coalsack: The Merging of Two Subsonic Flows?DOI: info:10.1088/0004-637X/690/2/1659v. 6901659–1671
Rathborne, J. M., Lada, Charles J., Walsh, W., Saul, M., and Butner, H. M. 2009. "The Dense Ring in the Coalsack: The Merging of Two Subsonic Flows?" The Astrophysical Journal, 690 1659–1671. https://doi.org/10.1088/0004-637X/690/2/1659.