Absolute positions of 6.7-GHz methanol masers Y. Xu, M. A. Voronkov, J. D. Pandian, J. J. Li, A. M. Sobolev, A. Brunthaler, B. Ritter and K. M. Menten A&A, 507 2 (2009) 1117-1139 Published online: 27 August 2009 DOI: 10.1051/0004-6361/200912135