@Article{ COLABORACIÓN_GONZÁLEZ:155-168,

author = { HTTP://WWW.AUGER.ORG COLABORACIÓN PIERRE AUGER and JAVIER GONZÁLEZ TABOADA } ,

title = { AN UPPER LIMIT TO THE PHOTON FRACTION IN COSMIC RAYS ABOVE 10**19-EV FROM THE PIERRE AUGER OBSERVATORY. },

journal = { ASTROPARTICLE PHYSICS },

year = { 2007 },

volume = { 27 },

issn = { 0927-6505 },

pages = { 155-168 },

}