Long-Term Effect of Botulinum Toxin in Impairment and Functional Health in Cervical DystoniaNeurol 50:1461-1463, Brans,J.W.M.,et al, 1998
Natural History of Adult-Onset Idiopathic TorticollisArch Neurol 47:548-552, Jahanshahi,M.,et al, 1990