poli tc social work G. Y. R. D. Zastrow C. H. & Kirst-Ashman K. K. (2016). Understanding human behavior and the social environment (10th ed.). Boston MA: Cengage Learning. Chapter 16 "Sociological Aspects of Later Adulthood" Tucker-Seeley Sorensen & Subramanian S. V. (2011). Lifecourse socioeconomic circumstances and multimorbidity among older adults. BMC Public Health 11(4) social work G. Y.