Tough E. A. et al.: Developing and validating a sham acupuncture needle. Acupunct Med 2009, 27 (3): 118–122.
Tan C. W. et al.: Discrimination of real and sham acupuncture needles using the park sham device: a preliminary study. Arch Phys Med Rehabil 2009, 90 (12): 2141–2145.
