https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-100 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-99 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-102 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-104 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-106 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-110 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-108 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-112 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-101 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-105 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-111 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-113 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-103 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-107 https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-5-109