Qaseem A, Forland F, Macbeth F, Ollenschläger G, Phillips S, van der Wees P (April 2012). “Guidelines International Network: toward international standards for clinical practice guidelines”. Ann. Intern. Med.156 (7): 525–31. doi:10.7326/0003-4819-156-7-201204030-00009. PMID22473437.。
Qaseem A, Forland F, Macbeth F, Ollenschläger G, Phillips S, van der Wees P (April 2012). “Guidelines International Network: toward international standards for clinical practice guidelines”. Ann. Intern. Med.156 (7): 525–31. doi:10.7326/0003-4819-156-7-201204030-00009. PMID22473437.。