1. Department of Social Work, The Chinese University of Hong Kong, Hong Kong, China
2. Gerontology Program, Departments of Political Science and Statistics, Iowa State University, Ames, Iowa, USA
3. Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong, China
4. Aging Specialization, University of Maryland School of Social Work, Maryland, USA
5. Department of Political Science, Iowa State University, Iowa, USA