Bauer D. J., & Hussong A. M. (2009). Psychometric approaches for developing commensurate measures across independent studies: Traditional and new models. Psychological Methods, 14, 101–125.
Bergeman C. S., Neiderhiser J. M., Pedersen N. L., & Plomin R. (2001). Genetic and environmental influences on social support in later life: A longitudinal analysis. International Journal of Aging & Human Development, 53, 107–135.
Boomsma D. I., Cacioppo J. T., Muthen B., Asparouhov T., & Clark S. (2007). Longitudinal genetic analysis for loneliness in Dutch twins. Twin Research and Human Genetics, 10, 267–273.
Cacioppo J. T., Hughes M. E., Waite L. J., Hawkley L. C., & Thisted R. A. (2006). Loneliness as a specific risk factor for depressive symptoms: Cross-sectional and longitudinal analyses. Psychology and Aging, 21, 140–151.
Christensen K., Doblhammer G., Rau R., & Vaupel J. W. (2009). Ageing populations: The challenges ahead. Lancet, 374, 1196–1208.
Christensen K., Holm N. V., McGue M., Corder L., & Vaupel J. W. (1999). A Danish population-based twin study on general health in the elderly. Journal of Aging and Health, 11, 49–64.
Christensen K., McGue M., Petersen I., Jeune B., & Vaupel J. W. (2008). Exceptional longevity does not result in excessive levels of disability. Proceedings of the National Academy of Sciences of the United States of America, 105, 13274–13279.
Christiansen L., Frederiksen H., Schousboe K., Skytthe A., von Wurmb-Schwark N., Christensen K., & Kyvik K. (2003). Age- and sex-differences in the validity of questionnaire-based zygosity in twins. Twin Research, 6, 275–278.
Cohen S. (2004). Social relationships and health. American Psychologist, 59, 676–684.
Cohen S., & Janicki-Deverts D. (2009). Can we improve our physical health by altering our social networks? Perspectives on Psychological Science, 4, 375–378.
Curran P. J., & Hussong A. M. (2009). Integrative data analysis: The simultaneous analysis of multiple data sets. Psychological Methods, 14, 81–100.
Embretson S. E., & Reise S. P. (2000). Item response theory for psychologists. Mahwah, NJ: Lawrence Erlbaum Associates.
Finkel D., & McGue M. (1993). The origins of individual differences in memory among the elderly: A behavior genetic analysis. Psychology and Aging, 8, 527–537.
Finkel D., & Pedersen N. L. (2004). Processing speed and longitudinal trajectories of change for cognitive abilities: The Swedish Adoption/Twin Study of Aging. Aging, Neuropsychology, and Cognition. Special Issue: Longitudinal Studies Of Cognitive Aging, 11, 325–345.
Gatz M., Johansson B., Pedersen N., Berg S., & Reynolds C. (1993). A cross-national self-report measure of depressive symptomatology. International Psychogeriatrics, 5, 147–156.
Gatz M., Pedersen N. L., Plomin R., Nesselroade J. R., & McClearn G. E. (1992). Importance of shared genes and shared environments for symptoms of depression in older adults. Journal of Abnormal Psychology, 101, 701–708.
Gold C. H., Malmberg B., McClearn G. E., Pedersen N. L., & Berg S. (2002). Gender and health: A study of older unlike-sex twins. Journals of Gerontology: Series B: Psychological Sciences and Social Sciences, 57B, S168–S176.
Hawkley L. C., & Cacioppo J. T. (2003). Loneliness and pathways to disease. Brain, Behavior, and Immunity, 17, S98–S105.
Jansson M., Gatz M., Berg S., Johansson B., Malmberg B., McClearn G. E., . . . Pedersen N. L. (2004). Gender differences in heritability of depressive symptoms in the elderly. Psychological Medicine, 34, 471–479.
Johnson W., & Krueger R. F. (2005a). Genetic effects on physical health: Lower at higher income levels. Behavior Genetics, 35, 579–590.
Johnson W., & Krueger R. F. (2005b). Higher perceived life control decreases genetic variance in physical health: Evidence from a national twin study. Journal of Personality and Social Psychology, 88, 165–173.
Kremen W. S., Thompson-Brenner H., Leung Y. J., Grant M. D., Franz C. E., Eisen S. A., . . . Lyons M. J. (2006). Genes, environment, and time: The Vietnam Era Twin Study of Aging (VETSA). Twin Research and Human Genetics, 9, 1009–1022.
Lykken D. T., Bouchard T. J., McGue M., & Tellegen A. (1990). The Minnesota Twin Family Registry: Some initial findings. Acta Gemellogicae et Medicae, 39, 35–70.
McClearn G. E., Johansson B., Berg S., Pedersen N. L., Ahern F., Petrill S. A., & Plomin R. (1997). Substantial genetic influence on cognitive abilities in twins 80 or more years old. Science, 276, 1560–1563.
McGue M., & Christensen K. (1997). Genetic and environmental contributions to depression symptomatology: Evidence from Danish twins 75 years of age and older. Journal of Abnormal Psychology, 106, 439–448.
McGue M., & Christensen K. (2007). Social activity and healthy aging: A study of aging Danish twins. Twin Research and Human Genetics, 10, 255–265.
McGue M., Hirsch B., & Lykken D. T. (1993). Age and the self-perception of ability: A twin study analysis. Psychology and Aging, 8, 72–80.
Neiderhiser J. M., & Lichtenstein P. (2008). The Twin and Offspring Study in Sweden: Advancing our understanding of genotype-environment interplay by studying twins and their families. Acta Psychologica Sinica, 40, 1116–1123.
Osler M., McGue M., Lund R., & Christensen K. (2008). Marital status and twins’ health and behavior: An analysis of middle-aged Danish twins. Psychosomatic Medicine, 70, 482–487.
Owens I. P. F. (2002). Ecology and evolution: Sex differences in mortality rate. Science, 297, 2008–2009.
Radloff L. S. (1977). The CES-D Scale: A self-report depression scale for research in the general population. Applied Psychological Measurement, 1, 385–401.
Rosenthal R. (1991). Meta-analytic procedures for social research (Rev. ed.). Newbury Park, CA: Sage.
Rosenthal R., & DiMatteo M. R. (2001). Meta-analysis: Recent developments in quantitative methods for literature reviews. Annual Review of Psychology, 52, 59–82.
Shanahan M. J., & Hofer S. M. (2005). Social context in gene-environment interactions: Retrospect and prospect. Journals of Gerontology: Series B: Psychological Sciences and Social Sciences, 60B (Special Issue 1), 65–76.
Schmalhausen I. (1946). Factors of evolution: The theory of stabilizing selection. Philadelphia: The Blakiston Company.
Schoeneborn C. A., & Heyman K. M. (2009). Health characteristics of adults aged 55 years and older: 2004–2007. In Department of Health and Human Services (DHHS) (Ed.), National Health Statistics Reports. Hyattsville, MD.
Velozo C. A., Byers K. L., Wang Y., & Joseph B. R. (2007). Translating measures across the continuum of care: Using Rasch analysis to create a crosswalk between the Functional Independence Measure and the Minimum Data Set. Journal of Rehabilitation Research and Development, 44, 467–478.