1. United Nations, Department of Economic and Social Affairs, Population Division. World population ageing: 1950–2050. New York: United Nations Publications; 2001.
2. Nieboer AP. Sustainable care in a time of crisis. Inaugural lecture, Erasmus University, Rotterdam, the Netherlands, November 1, 2013.
3. Diener E. Subjective well-being. Psychol Bull. 1984;95:542–75.
4. Watson D. The vicissitudes of mood measurement: effects of varying descriptors, time frames, and response formats on measures of positive and negative affect. J Personal Soc Psychol. 1988;55:128–41.
5. Lindenberg S. Continuities in the theory of social production functions. In: Ganzeboom H, Lindenberg S, editors. Verklarende Sociologie; Opstellen Voor Reinhart Wippler. Amsterdam: Thesis Publications; 1996.