1. Discipline of Chiropractic, School of Health, Medical and Applied Science, CQ University, Brisbane, QLD 4701, Australia
2. Department of Clinical Education, Canadian Memorial Chiropractic College, Toronto, ON M2H 3J1, Canada
3. Center for Occupational and Environmental Health, University of California, Irvine, CA 92093, USA
4. Office of Public Health Studies, Thompson School of Social Work & Public Health, University of Hawaii, Mānoa, Honolulu, HI 96822, USA
5. Employer Based Integrated Primary Care Health Centers, Stanford Health Care, San Diego, CA 92121, USA
6. Department of Publications, National University of Health Sciences, Lombard, IL 60148, USA
7. Department of Neurology, University of California, Irvine, CA 92093, USA