https://bmcmedresmethodol.biomedcentral.com/articles/10.1186/1471-2288-10-103
https://bmcmedresmethodol.biomedcentral.com/articles/10.1186/1471-2288-10-105
https://bmcmedresmethodol.biomedcentral.com/articles/10.1186/1471-2288-10-104
https://bmcmedresmethodol.biomedcentral.com/articles/10.1186/1471-2288-10-106