APA

Posner R. A., . (1990). The problems of jurisprudence. Cambridge, Mass: Harvard University Press.

Chicago

Posner Richard A, . 1990. The problems of jurisprudence. Cambridge, Mass: Harvard University Press.

Harvard

Posner R. A., . (1990). The problems of jurisprudence. Cambridge, Mass: Harvard University Press.

MLA

Posner Richard A, . The problems of jurisprudence. Cambridge, Mass: Harvard University Press. 1990.