O'Brien, Jodi (2009). Encyclopedia of Gender and Society. SAGE Publications. էջ 155. ISBN9781412909167. Վերցված է 2014 թ․ հունիսի 19-ին. «In this subset of abstinence-only education programs, young people vow chastity until marriage and wear a "purity ring" to demonstrate a commitment to sexual abstinence.»
