1. Appleton, A. B. andSimon, G. (1958)Surface and radiological anatomy. 4th edn. pp. 124–126, 173–174. W. Heffer, Cambridge.
2. Brown, J. G. (1883)Medical diagnosis: a manual of clinical methods. 2nd edn. Bell and Bradfute, Edinburgh.
3. Cabot, R. C. (1906)Physical diagnosis. 3rd edn. Bailliere, Tindall and Cox, London.
4. Casteleijn, G. (1961)Physical investigations on percussion. Bronder-Offset, Rotterdam.
5. Coleman, W. (1939), The role of vibration sense in percussion.Am. J. Med. Sci.,197, 145–151.