APA

Thirlway Hugh, . (2019). The sources of international law. New York: Oxford University Press.

Chicago

Thirlway Hugh, . 2019. The sources of international law. New York: Oxford University Press.

Harvard

Thirlway Hugh, . (2019). The sources of international law. New York: Oxford University Press.

MLA

Thirlway Hugh, . The sources of international law. New York: Oxford University Press. 2019.