T. Alexander Aleinikoff and Douglas B. Klusmeyer, eds., From Migrants to Citizens: Membership in a Changing World (Washington, DC: Carnegie Endowment for International Peace, 2000), 1-21; Gerhard Casper, “The Concept of National Citizenship in the Contemporary World: Identity or Volition?” (Hamburg, Germany: Bucerius Law School, 2008).
