Παραπομπή σε μορφή APA (7η εκδ.)

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

Παραπομπή σε μορφή Chicago (17η εκδ.)

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

Παραπομπή σε μορφή MLA (9th εκδ.)

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