APA (7th ed.) Citation

Walker, A. M. (1991). Observation and inference: An introduction to the methods of epidemiology. Epidemiology Resources Inc..

Chicago Style (17th ed.) Citation

Walker, Alexander Muir. Observation and Inference: An Introduction to the Methods of Epidemiology. Chestnut Hill, MA: Epidemiology Resources Inc., 1991.

MLA (9th ed.) Citation

Walker, Alexander Muir. Observation and Inference: An Introduction to the Methods of Epidemiology. Epidemiology Resources Inc., 1991.

Warning: These citations may not always be 100% accurate.