1. Stockholm Congress of Radiology, 1928.
2. Chicago Congress of Radiology, 1937.
3. International Commission on Radiological Protection, Brit. J. Radiol. Supplement 6, 1955.
4. International Commission on Radiological Units, Copenhagen, 1953, Brit. J. Radiol. 27, 243, 1954.
5. Brit. J. Radiol. 29, 355, 1956.