US Department of Health and Human Services. National Institutes of Health. Eunice Kennedy Shriver Institute of Child Health and Human Development. What are the different types of contraception? https://www.nichd.nih.gov/health/topics/contraception/conditioninfo/Pages/types.aspx. Updated January 31, 2017. Accessed January 2019.
Barrier methods of birth control: spermicide, condom, sponge, diaphragm, and cervical cap. The American College of Obstetricians and Gynecologists. FAQ 022, March 2018. https://www.acog.org/Patients/FAQs/Barrier-Methods-of-Birth-Control-Spermicide-Condom-Sponge-Diaphragm-and-Cervical-Cap. Accessed February 2019.
Spermicide. Planned Parenthood. https://www.plannedparenthood.org/learn/birth-control/spermicide. Accessed February 2019.