Gonnot, J.-P. <https://pure.iiasa.ac.at/view/iiasa/1913.html>, Keilman, N., & Prinz, C. <https://pure.iiasa.ac.at/view/iiasa/1520.html>  (1995).  Social Security, Household and Family Dynamics in Aging Societies.     Dordrecht: Kluwer Academic Publishers.  ISBN 0-7923-3395-0