@article{article644b3b75,
title   = {Trigger and aperture of the surface detector array of the Pierre Auger Observatory},
author = {Abraham, J and Souza, Vitor de and Gouffon, Philippe and Tridapalli, D. B.},
year = {2010},
doi = {10.1016/j.nima.2009.11.018},
journal   = {Nuclear Instruments and Methods in Physics Research A}
}