Cazals, Catherine, Dudley, Paul, Florens, Jean-Pierre and Jones, Michael (2012) A panel data analysis of inefficiency and heterogeneity in the postal sector. In: Multi-Modal Competition and the Future of Mail Crew, Michael A. and Kleindorfer, Paul R. (eds.) Michael A. Crew and Paul R. Kleindorfer. Chapter 8. pp. 109-123. ISBN 9780857935816

Cazals, Catherine, Dudley, Paul, Florens, Jean-Pierre and Jones, Michael (2011) The Effect of Unobserved Heterogeneity in Stochastic Frontier Estimation: Comparison of Cross Section and Panel with Simulated Data for The Postal Sector. Review of Network Economics, 10 (3).

Cazals, Catherine, Dudley, Paul, Florens, Jean-Pierre and Jones, Michael (2010) The Effect of Unobserved Heterogeneity in Stochastic Frontier Estimation: Comparison of Cross Section and Panel with Simulated Data for The Postal Sector. TSE Working Paper, n. 10-173