Green, J. A., Breen, S. L., Fuller, G. A., McClure-Griffiths, N. M., Ellingsen, S. P., Voronkov, M. A., Avison, A., Brooks, K., Burton, M. G. et al (2017) The 6-GHz multibeam maser survey – II. Statistical analysis and Galactic distribution of 6668-MHz methanol masers. Monthly Notices of the Royal Astronomical Society, 469 (2). pp. 1383-1402. ISSN 0035-8711