BibTex format
@article{Cowling:2013:10.1136/bmj.f7570,
author = {Cowling, TE and Harris, MJ and Soljak, MA and Majeed, A},
doi = {10.1136/bmj.f7570},
journal = {British Medical Journal},
title = {Opening hours of general practices in England},
url = {http://dx.doi.org/10.1136/bmj.f7570},
volume = {347},
year = {2013}
}