Ann Ashburn, Ruth M. Pickering, Louise Fazakarley, Claire Ballinger, Lindsay D. McLellan & Carolyn Fitton,
2007, Parkinsonism and Related Disorders, 13(1), 35-39
A. Ashburn, L. Fazarkarley, C. Ballinger, R. Pickering, L. McLellan & C. Fitton,
2007, Journal of Neurology, Neurosurgery and Psychiatry, 78(7), 678-684