1. Coombs, C. H. (1950). Psychological scaling without a unit of measurement. Psychological Review, 57, 148–158.
2. Coombs, C. H. (1953). Theory and methods of social measurements. In L. Festinger & D. Katz (Eds.), Research methods in the behavioral sciences. New York: Dryden Press.
3. Coombs, C. H. (1964). A theory of data. Ann Arbor: Mathesis.
4. Sage University Paper Series on Quantitative Applications in the Social Sciences, series no. 07-078;WG Jacoby,1991
5. Maggino, F. (2009). The state of the art in indicators construction in the perspective of a comprehensive approach in measuring well-being of societies. Firenze: Firenze University Press, Archivio E-Prints. Published also in Global Progress Research Network (GPRNet) Wikiprogress page http://wikiprogress.org/index.php/Filomena_Maggino. Accepted 21 Jan 2010.