The diversity of methanol maser morphologies from VLBI observations A. Bartkiewicz, M. Szymczak, H. J. van Langevelde, A. M. S. Richards and Y. M. Pihlström A&A, 502 1 (2009) 155-173 Published online: 27 May 2009 DOI: 10.1051/0004-6361/200912250