2[2]Gans, Joshua S ;King, Stephen P. and Woodbridge, Graeme2001 . "Numbers to the People: Regulation, Ownership,and Local Number Portability," Information Economics and Policy 13,167-180.
3[3]Haucap, Justus, "Telephone Number Allocation: A Property Rights Approach"European Journal of Law and Economics, 15, 2003, 91-109 .