Spectroscopic binaries among Hipparcos M giants - II. Binary frequency A. Frankowski, B. Famaey, S. Van Eck, M. Mayor, S. Udry and A. Jorissen A&A, 498 2 (2009) 479-488 Published online: 18 February 2009 DOI: 10.1051/0004-6361/200810702