Rotational period of GQ Lupi C. Broeg, T. O. B. Schmidt, E. Guenther, A. Gaedke, A. Bedalov, R. Neuhäuser and F. M. Walter A&A, 468 3 (2007) 1039-1044 Published online: 24 April 2007 DOI: 10.1051/0004-6361:20066793