Cassell, J. A., Mercer, C. H., Sutcliffe, L., Petersen, I., Islam, A., Brook, M. G., et al. (2006). Trends in sexually transmitted infections in general practice 1990-2000: population based study using data from the UK general practice research database. Bmj. http://doi.org/10.1136/bmj.38726.404120.7C
Evans, H. E., Mercer, C. H., Rait, G., Hamill, M., Delpech, V., Hughes, G., et al. (2009). Trends in HIV testing and recording of HIV status in the UK primary care setting: a retrospective cohort study 1995-2005. Sex Transm Infect. http://doi.org/10.1136/sti.2008.034801