Willis S L, Martin M, Rocke C
Seattle Longitudinal Study, University of Washington, Seattle, WA USA.
Department of Gerontopsychology, University of Zurich, Binzmuehlestr. 14/Box 24, 8050 Zürich, Switzerland.
Eur J Ageing. 2010 Sep 14;7(3):131-134. doi: 10.1007/s10433-010-0162-4. eCollection 2010 Sep.