Whelan, C., R. Layte, B. Maître and B. Nolan (2001). Persistent Income Poverty and Deprivation in the European Union: An Analysis of the First Three Waves of the European Community Household Panel, Colchester: University of Essex, https://www.esri.ie/publications/persistent-income-poverty-and-deprivation-in-the-european-union-an-analysis-of-the-first-three-waves-of-the-european-community-household-panel