APA (7th ed.) Citation

Rothwell, P. (2006). Factors that can affect the external validity of randomised controlled trials.

Chicago Style (17th ed.) Citation

Rothwell, P. Factors That Can Affect the External Validity of Randomised Controlled Trials. 2006.

MLA (9th ed.) Citation

Rothwell, P. Factors That Can Affect the External Validity of Randomised Controlled Trials. 2006.

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