Nico Schrijver holds the Chair of International Law and is Academic Director of the Grotius Centre for International Legal Studies at Leiden University. He is author of The Evolution of Sustainable Development in International Law: Inception, Meaning, and Status and Sovereignty over Natural Resources: Balancing Rights and Duties.
Hans Kruuk is Honorary Professor of Zoology, University of Aberdeen and Senior Principal Scientific Officer (Retired) at the Centre for Ecology and Hydrology, Banchory.