8. Farnsworth NR, ed. NAPRALERT database. Chicago, IL, University of Illinois at Chicago, 9 February 2001 production (an online database available directly through the University of Illinois at Chicago or through the Scientific and Technical Network (STN) of Chemical Abstracts Services)
17. Schmidt S. Rheumatherapie mit Harpagophytum. [Treatment of rheumatism with Harpagophytum.] Therapiewoche, 1972, 13:1072–1075.
18. Chrubasik S et al. Effectiveness of Harpagophytum procumbens in treatment of acute low back pain. Phytomedicine, 1996, 3:1–10.
19. Stange CF, Schultz J. Treatment of low back pain with Harpagophytum procumbens (Burch.) De Candolle (“devil’s claw”). Erfahrungsheilkunde, 1997, 6:330–335.
20. Chrubasik S et al. Effectiveness of Harpagophytum extract WS 1531 in the treatment of exacerbation of low back pain: a randomized, placebo-controlled, double-blind study. European Journal of Anaesthesiology, 1999, 16:118–129.
21. Wegener T. Therapie degenerativer Erkrankungen des Bewegungsapparates mit sudafrikanischer Teufelskralle
(Harpagophytum procumbens D.C.). [Treatment of degenerative diseases of the locomotor system with south
African devil’s claw (Harpagophytum procumbens D.C.).] Wiener Medizinische Wochenschrift, 1999, 149:254–257.
22. Chantre P et al. Efficacy and tolerance of Harpagophytum procumbens versus diacerhein in the treatment of osteoarthritis. Phytomedicine, 2000, 7:177–183.
23. Frerick H, Biller A, Schmidt U. Stufenschema bei coxarthrose. [Graded approach to the treatment of coxarthrosis.]
Der Kassenarzt , 2001, 5:34–41
24. Göbel H et al. Harpagophytum-Extrakt LI174 (Teufelskralle) bei der Behandlung unspezifischer Rückenschemerzen. Effekte auf die sensible, motorische und vaskuläre Muskelreagibilität. [Harpagophytum-extract LI174 (devil’s claw) for the treatment of non-specific back pain. Effects on sensory, motor and vascular muscle responsiveness.] Schmerz, 2001, 15:10–18.
25. Blumenthal M et al., eds. The complete German Commission E monographs, Austin, TX, American Botanical Council, 1998.
