?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Etxaluze%2C+M&rft.aufirst=M&rft.aulast=Etxaluze&rft.volume=566&rft.issn=0004-6361&rft.title=Astronomy+and+Astrophysics&rft.atitle=Herschel+spectral+mapping+of+the+Helix+nebula+(NGC+7293)%3A+Extended+CO+photodissociation+and+OH%2B+emission&rft.date=June+2014&rft.genre=article