Income and wealth distribution, inequality and poverty : proceedings of the second International Conference on Income Distribution by Size: Generation, Distribution, Measurement and Applications, held at the University of Pavia, Italy, September 28-30, 1989 - International Conference on Income Distribution by Size: Generation, Distribution, Measurement, and Applications; Dagum, Camilo; Zenga, Michele; Università di Pavia (Studies in contemporary economics, 1990)