Working paper The impact of increasing competition for non-contract parcels on postal prices and efficiency decisions Philippe De Donder, Frank Rodriguez, and Soterios Soteri n. 886, May 2018 ReferencePhilippe De Donder, Frank Rodriguez, and Soterios Soteri, “The impact of increasing competition for non-contract parcels on postal prices and efficiency decisions”, IDEI Working Paper, n. 886, May 2018.