“In Memoriam: Eric Stein” Halberstam, Daniel H. Ratner, Steven R. Reimann, Mathias W. MLaw Repository WWW HEIN International and Comparative Law American Journal of International Law 2012 Federalism and Legal Unification: A Comparative Empirical Investigation of Twenty Systems Halberstam, Daniel H. Reimann, Mathias W. International and Comparative Law 2012