Cremer, Helmuth, Grimaud, André and Laffont, Jean-Jacques (2000) The Cost of Universal Service in the Postal Sector. In: Current Directions in Postal Reform Crew, Michael A. and Kleindorfer, Paul R. (eds.) Springer. Series “Topics in Regulatory Economics and Policy”, Vol. 35. Chapter 3. pp. 47-68. ISBN 978-1-4615-4481-4