1. Brit. Pat. Application 25395/56, D. P. C. Thackeray 20/8/56, assigned to National Research Development Corporation.
2. Proc. Third International Congress on High Speed Photography, 42 (Butterworths, London, 1956).
3. Brit. Pat. Application 19640/57, D. P. C. Thackeray 21/6/57, assigned to National Research Development Corporation.