BibTex format
@article{Perez-Hernandez:2011:10.1364/OE.19.019430,
author = {Perez-Hernandez, JA and Roso, L and Zair, A and Plaja, L},
doi = {10.1364/OE.19.019430},
journal = {OPTICS EXPRESS},
pages = {19430--19439},
title = {Valley in the efficiency of the high-order harmonic yield at ultra-high laser intensities},
url = {http://dx.doi.org/10.1364/OE.19.019430},
volume = {19},
year = {2011}
}