RT Journal Article SR Electronic T1 Handbook of Parkinson’s Disease ed. William C. Koller JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 483 OP 483 VO 55 IS 5 A2 Zakov, Z. Nicholas A1 Hanson, Maurice YR 1988 UL http://www.ccjm.org/content/55/5/483.1.abstract AB