1. Multiple Sclerosis Centre Nijmegen, Heiweg 97, 6533 PA Nijmegen, The Netherlands,
2. Foundation for Innovative Research and Education on Complementary Medicine, Spoorlaan 2a, 3735 MV Bosch en Duin, The Netherlands
3. MS4 Research Institute, Ubbergseweg 34, 6522 KJ Nijmegen, The Netherlands
4. Department of Epidemiology and Biostatistics, EMGO Institute, VU University Medical Centre. De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
5. Dutch Medical Society of Acupuncture, Post bus 8003, 6440 HA Brunssum, The Netherlands