Interstellar chemistry of nitrogen hydrides in dark clouds R. Le Gal, P. Hily-Blant, A. Faure, G. Pineau des Forêts, C. Rist and S. Maret A&A, 562 (2014) A83 Published online: 12 February 2014 DOI: 10.1051/0004-6361/201322386