Myasthenia Gravis as a Cause of Head Drop in Parkinson DiseaseThe Neurologist 17:144-146, Uludag, I.F.,et al, 2011
The Dropped Head Sign: An Unusual Presenting Feature of Myasthenia GravisNeuromuscul Disord 14:378-379, Puruckherr,M.,et al, 2004