BibTex format
@article{Greenfield:2021:10.1136/bmjopen-2021-051409,
author = {Greenfield, G and Okoli, O and Quezada, Yamamoto H and Blair, M and Saxena, S and Majeed, F and Hayhoe, B},
doi = {10.1136/bmjopen-2021-051409},
journal = {BMJ Open},
pages = {1--7},
title = {Characteristics of frequently attending children in hospital emergency departments: a systematic review},
url = {http://dx.doi.org/10.1136/bmjopen-2021-051409},
volume = {11},
year = {2021}
}