@book{gledocs_11858_00-1735-0000-0001-31A6-C,
author = {Ulrich, Ralf Matthias},
title = {Measurement of the proton air cross section using hybrid data of the Pierre Auger Observatory},
year = {2008},
publisher = {Univ. Karlsruhe},

note = { \url {http://hdl.handle.net/11858/00-1735-0000-0001-31A6-C}},
}