Ortho-to-para ratio of NH2 - Herschel-HIFI observations of ortho- and para-NH2 rotational transitions towards W31C, W49N, W51, and G34.3+0.1
C. M. Persson, A. O. H. Olofsson, R. Le Gal, E. S. Wirström, G. E. Hassel, E. Herbst, M. Olberg, A. Faure, P. Hily-Blant, J. H. Black, M. Gerin, D. Lis and F. Wyrowski
