References
- Exner and Packard (1935) Radiol, 25, p. 391.
- Henshaw and Francis (1936) Radiol, 27, p. 569.
- Packard (1940) Radiol, 34, p. 17.
- Stone (1938) Radiol, 30, p. 88.
- Witwer and Leucutia (1940) Radiol, 34, p. 24.
- Hoed, Den (1935) Radiol, 25, pp. 57-81.