"The chapters in this collection were amongst those presented at the 2011 International Law Association British Branch annual conference held at the University of Sheffield" -- preface.
OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
Statehood and self-determination : reconciling tradition and modernity in international law. ISBN 9781107029330. Published by Cambridge University Press in 2013. Publication and catalogue information, links to buy online and reader comments.
