BibTex format
@article{Cook:2018:10.1136/bmj.k3750,
author = {Cook, JA and Julious, SA and Sones, W and Hampson, L and Hewitt, C and Berlin, JA and Ashby, D and Emsley, R and Fergusson, DA and Walters, SJ and Wilson, ECF and MacLennan, G and Stallard, N and Rothwell, JC and Bland, M and Brown, L and Ramsay, CR and Cook, A and Armstrong, D and Altman, D and Vale, LD},
doi = {10.1136/bmj.k3750},
journal = {BMJ-BRITISH MEDICAL JOURNAL},
title = {DELTA(2) guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial},
url = {http://dx.doi.org/10.1136/bmj.k3750},
volume = {363},
year = {2018}
}