Excitation of H2 in photodissociation regions as seen by SpitzerE. Habart, A. Abergel, F. Boulanger, C. Joblin, L. Verstraete, M. Compiègne, G. Pineau des Forêts and J. Le BourlotA&A, 527 (2011) A122DOI: https://doi.org/10.1051/0004-6361/20077327