Southard, H. (1971). Sex before twenty: New answers for young people (Rev. ed.). Dutton.
芝加哥风格引文Southard, Helen. Sex Before Twenty: New Answers for Young People. Rev. ed. New York: Dutton, 1971.
MLA引文Southard, Helen. Sex Before Twenty: New Answers for Young People. Rev. ed. Dutton, 1971.
警告：这些引文格式不一定是100％准确.