Hyde, M., Hyde, M., Wiggins, R., Higgs, P., & Blane, D. (2003). A measure of quality of life in early old age: The theory, development and properties of a needs satisfaction model (CASP-19). Aging & Mental Health, 7(3), pp. 186-194. doi:10.1080/1360786031000101157

Hyde, Martin, M. Hyde, R.D Wiggins, P. Higgs, and D.B Blane. "A Measure of Quality of Life in Early Old Age: The Theory, Development and Properties of a Needs Satisfaction Model (CASP-19)." Aging & Mental Health 7, no. 3 (2003): 186-194.

Hyde, Martin, et al. "A Measure of Quality of Life in Early Old Age: The Theory, Development and Properties of a Needs Satisfaction Model (CASP-19)." Aging & Mental Health 7.3 (2003): 186-194.