Post-common-envelope binaries from SDSS - IX: Constraining the common-envelope efficiency M. Zorotovic, M. R. Schreiber, B. T. Gänsicke and A. Nebot Gómez-Morán A&A, 520 (2010) A86 Published online: 07 October 2010 DOI: 10.1051/0004-6361/200913658