Higgins, J. P. and Altman, D. G. (2008)
Assessing
Risk of Bias in Included Studies
Cochrane Handbook for Systematic Reviews of Interventions:
Cochrane Book Series (eds J. P. Higgins and S. Green), John Wiley & Sons, Ltd,
Chichester, UK. doi: 10.1002/9780470712184.ch8