Villa, V. (1997). A definition of legal positivism. Challenges to law at the end of the 20th century ; 4: Legal systems and legal science, 22 - 29.
芝加哥风格引文Villa, Vittorio. "A Definition of Legal Positivism." Challenges to Law at the End of the 20th Century ; 4: Legal Systems and Legal Science 1997: 22 - 29.
MLA引文Villa, Vittorio. "A Definition of Legal Positivism." Challenges to Law at the End of the 20th Century ; 4: Legal Systems and Legal Science, 1997, pp. 22 - 29.
警告：这些引文格式不一定是100％准确.