The nature of the methanol maser ring G23.657-00.127 - I. The distance through trigonometric parallax measurementsA. Bartkiewicz, A. Brunthaler, M. Szymczak, H. J. van Langevelde and M. J. ReidA&A, 490 2 (2008) 787-792DOI: https://doi.org/10.1051/0004-6361:200810470
