SpringerLink (Online service), Parfrey, P. S., & Barrett, B. J. (2015). Clinical Epidemiology: Practice and Methods (2nd ed. 2015.). Springer New York : Imprint: Humana. https://doi.org/10.1007/978-1-4939-2428-8

SpringerLink (Online service), Patrick S. Parfrey, and Brendan J. Barrett. Clinical Epidemiology: Practice and Methods. 2nd ed. 2015. New York, NY: Springer New York : Imprint: Humana, 2015. https://doi.org/10.1007/978-1-4939-2428-8.

SpringerLink (Online service), et al. Clinical Epidemiology: Practice and Methods. 2nd ed. 2015. Springer New York : Imprint: Humana, 2015. https://doi.org/10.1007/978-1-4939-2428-8.