1. Campbell, E., and Whitfield, R. D. (1948). J. Neurosurg., 5, 131.
2. Castellano, F., and Ruggiero, G. (1953). Acta radiol. (Stockh.), Suppl.
3. Cushing, H., and Eisenhardt, L. (1938). Meningiomas, p. 181. Thomas, Springfield, Illinois.
4. D'Errico, A. (1950). J. Neurosurg., 7, 227.
5. Hamby, W. B. (1947). Ibid., 4, 179.