- &quot; Complementarity of International Treaty Law, Customary Law, and Non-Contractual Law Making &quot; en R. Wolfrum y V. Röben, Developments of International Law en Treaty-Making, Springer, Berlín, 2005.
- &quot; Complementarity of International Treaty Law, Customary Law, and Non-Contractual Law Making &quot; dans R. Wolfrum et V. Röben, Developments of International Law in Treaty-Making, Springer, Berlin, 2005