1. Patton ME, Su JR, Nelson R, Weinstock H. Primary and secondary syphilis—United States, 2005–2013. Morb. Mortal. Wkly. Rep. 2014;63:402–6.
2. Dougan S, Evans BG, Elford J. Sexually transmitted infections in Western Europe among HIV-positive men who have sex with men. Sex Transm Dis. 2007;34:783–90.
3. The Kirby Institute. HIV, viral hepatitis and sexually transmissable infections in Australia Annual Surveillance Report 2013. The University of SoutH Wales, Sydney NSW 2052: The Kirby Institute.
4. Verma K. P3.086 changing patterns of syphilis in Asia-pacific. Sex Transm Infect. 2013;89:A174–4.
5. Public Health Agency of Canada. Report on sexually transmitted infections in Canada. Ottawa: Centre for Communicable Diseases and Infection Control, Infectious Disease Prevention and Control Branch; 2012.