BibTex format
@unpublished{Alturkistani:2019:10.2196/preprints.14975,
author = {Alturkistani, A and Greenfield, G and Greaves, F and Aliabadi, S and Jenkins, RH and Costelloe, C},
doi = {10.2196/preprints.14975},
publisher = {JMIR Publications},
title = {Patient portal functionalities and uptake: systematic review protocol (Preprint)},
url = {http://dx.doi.org/10.2196/preprints.14975},
year = {2019}
}