Circumstellar H I and CO around the carbon stars V1942 Sagittarii and V Coronae Borealis Y. Libert, E. Gérard, C. Thum, J. M. Winters, L. D. Matthews and T. Le Bertre A&A, 510 (2010) A14 Published online: 29 January 2010 DOI: 10.1051/0004-6361/200913278