Kelsey, J. L. W. (1996). Methods in observational epidemiology (2nd.). Oxford University Press.

Kelsey, Jennifer L. Whittemore. Methods in Observational Epidemiology. 2nd. New York: Oxford University Press, 1996.

Kelsey, Jennifer L. Whittemore. Methods in Observational Epidemiology. 2nd. Oxford University Press, 1996.