US Department of Health and Human Services. National Institutes of Health. Eunice Kennedy Shriver National Institute of Child Health and Human Development. What are some types of sexually transmitted diseases or sexually transmitted infections (STDs/STIs)? https://www.nichd.nih.gov/health/topics/stds/conditioninfo/Pages/types.aspx. Accessed February 2017.
Centers for Disease Control and Prevention. Sexually transmitted diseases (STDs). https://www.cdc.gov/STD/. Updated November 2015. Accessed February 2017.
Centers for Disease Control and Prevention. Condom fact sheet in brief. https://www.cdc.gov/condomeffectiveness/brief.html. Updated March 25, 2017. Accessed February 2017.
STDs. Planned Parenthood. https://www.plannedparenthood.org/learn/stds-hiv-safer-sex. Accessed February 2017.