Measuring the tensor to scalar ratio from CMB B-modes in the presence of foregrounds M. Betoule, E. Pierpaoli, J. Delabrouille, M. Le Jeune and J.-F. Cardoso A&A, 503 3 (2009) 691-706 Published online: 27 May 2009 DOI: 10.1051/0004-6361/200911624