APA (7th ed.) Citation

Oppenheim, L., Watts, A., & Jennings, R. Y. (2011). Oppenheim's international law (9th ed., repr.). Oxford University Press.

Chicago Style (17th ed.) Citation

Oppenheim, L., Arthur Watts, and R. Y. Jennings. Oppenheim's International Law. 9th ed., repr. Oxford [etc.]: Oxford University Press, 2011.

MLA (9th ed.) Citation

Oppenheim, L., et al. Oppenheim's International Law. 9th ed., repr. Oxford University Press, 2011.