For the use of a Best Evidence Synthesis, I would like to refer to the criteria of van Tulder.
Tulder M.W.V.A., Cherkin D.C., Berman B., Lao L., Koes B.W. (2000). Acupuncture for low back pain. Cochrane Database Syst Rev. (2):CD001351.
However, his full-text articles are not available for my school. Can anybody find this, or one of his more updated, articles? Please contact me.