1. Beneke, R. (1908). Arch. Kinderheilk., 47, 420.
2. Blackwood, W., and Cumings, J. H. (1954). J. Neurol. Psychiat., 17, 33.
3. Collier, J., and Greenfield. J. G. (1924). Brain, 47, 489.
4. Cerebr;Hagberg, B.; Sourander, P.; Svennerholm, L.,1961
5. Palsy Bull., 3, 438. -, -,,and Voss, H. (1960). Acta paediat., (Uppsala), 49, 135.