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
Hughes, G., Williams, T., Simms, I., Mercer, C., Fenton, K., & Cassell, J. (2007). Use of a primary care database to determine trends in genital chlamydia testing, diagnostic episodes and management in UK general practice, 1990-2004. Sex Transm Infect. http://doi.org/10.1136/sti.2006.022673