APA Citation

Parfrey, P. S., & Barrett, B. J. Clinical epidemiology: Practice and methods.

Chicago Style Citation

Parfrey, Patrick S., and Brendan J. Barrett. Clinical Epidemiology: Practice and Methods.

MLA Citation

Parfrey, Patrick S., and Brendan J. Barrett. Clinical Epidemiology: Practice and Methods.

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