BibTex format
@article{Zepf:2008:10.1103/PhysRevLett.100.199501,
author = {Zepf, M and Krushelnick, K and Dangor, AE},
doi = {10.1103/PhysRevLett.100.199501},
journal = {PHYSICAL REVIEW LETTERS},
title = {Comment on "Plasma Modulation of Harmonic Emission Spectra from Laser-Plasma Interactions"},
url = {http://dx.doi.org/10.1103/PhysRevLett.100.199501},
volume = {100},
year = {2008}
}