Herschel/HIFI observations of [C II] and [13C II] in photon-dominated regions V. Ossenkopf, M. Röllig, D. A. Neufeld, P. Pilleri, D. C. Lis, A. Fuente, F. F. S. van der Tak and E. Bergin A&A, 550 (2013) A57 Published online: 24 January 2013 DOI: 10.1051/0004-6361/201219837