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webmd.com - Parkinson's Disease Center: Symptoms, Treatments, Causes ...
wikipedia.org - Parkinson's disease - Wikipedia
medicinenet.com - Parkinson's Disease Early and Later Symptoms, 5 Stages ...
parkinson.org - Parkinson's Foundation: Better Lives. Together.
medlineplus.gov - Parkinson's Disease | PD | MedlinePlus
alz.org - Parkinson's Disease Dementia | Symptoms & Treatments | alz.org
nih.gov - Parkinson's Disease - National Institute on Aging
drugs.com - Parkinson Disease - What You Need to Know - Drugs.com