TY - JOUR AN - 7 AU - Hughes,A.J. AU - Lees,A.J. AU - Stern,G.M. TI - Challenge tests to predict the dopaminergic response in untreated Parkinson's disease. JO - Neurology PY - 1991 VL - 41 SP - 1723-1725 M2 - 1723 ER -