1. Bonita R, Beaglehole R, Kjellstrom T. Basic epidemiology. Geneva: World Health Organization; 2006.
2. Little WJ. On the influence of abnormal parturition, difficult labours, premature birth, and asphyxia neonatorum on the mental and physical condition of the child, especially in relation to deformities. Trans Obstet Soc Lond. 1862;3:293–344.
3. Osler W. The cerebral palsies of childhood. London, HK: Lewis; 1889.
4. Bax MC. Terminology and classification of cerebral Palsy. Dev Med Child Neurol. 1964;6:295–7.
5. Freud S. Infantile cerebral paralysis. Coral Gables, Fla, USA: University of Miami Press; 1968.