Nonmotor Fluctuations in Patients with Parkinson's DiseaseNeurol 47:1180-1183, Hillen,M.E.&Sage,J.I., 1996
The Spectrum of Levodopa-Related Fluctuations in Parkinson's DiseaseNeurol 43:1459-1464, Riley,D.E.&Lang,A.E., 1993