Systems for grading the quality of evidence and the strength of recommendations II: pilot study of a new system.
Atkins D, Briss PA, Eccles M, Flottorp S, Guyatt GH, Harbour RT, Hill S, Jaeschke R, Liberati A, Magrini N, et al. BMC Health Serv Res. 2005 Mar 23; 5(1):25. Epub 2005 Mar 23.