APA استشهاد

Richard,, S. (2000). Principles of contract law (4.). Cavendish.

استشهاد بنمط شيكاغو

Richard,, Stone. Principles of Contract Law. 4. London: Cavendish, 2000.

MLA استشهاد

Richard,, Stone. Principles of Contract Law. 4. Cavendish, 2000.