Rothwell, P. (2006). Factors that can affect the external validity of randomised controlled trials.
Chicago-čujuhus (17. p.)Rothwell, P. Factors That Can Affect the External Validity of Randomised Controlled Trials. 2006.
MLA-čujuhus (9. p.)Rothwell, P. Factors That Can Affect the External Validity of Randomised Controlled Trials. 2006.
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