Identification of 13 DB + dM and 2 DC + dM binaries from the Sloan Digital Sky Survey E. J. M. van den Besselaar, G. H. A. Roelofs, G. A. Nelemans, T. Augusteijn and P. J. Groot A&A, 434 3 (2005) L13-L16 Published online: 18 April 2005 DOI: 10.1051/0004-6361:200500102