BibTex format
@inbook{Arulkumaran:2013:10.1016/j.bpobgyn.2013.08.006,
author = {Arulkumaran, N and Rhodes, A},
doi = {10.1016/j.bpobgyn.2013.08.006},
title = {Critical illness in obstetrics. Preface.},
url = {http://dx.doi.org/10.1016/j.bpobgyn.2013.08.006},
year = {2013}
}