- Parkinson’s Disease Society. The professionals guide to Parkinson’s disease. 2007 [cited 2013 Mar 11]. Available from: http://pdcenter.neurology.ucsf.edu/professionals-guide
- National Collaborating Centre for Chronic Disease. Parkinson’s disease: national clinical guideline for diagnosis and management in primary and secondary care. London: Royal College of Physicians; 2006 [cited 2013 Mar 11]. Available from: https://www.nice.org.uk/guidance/cg35
- Cereda E, Barichella M, Pedrolli C,