1. O'Brien W. J. , Hawker H. G. and The Decca Record Co. (1954), British Patent Specification 765,573 (application date March 1954).
2. Hyperbolic Origins
3. Obituary notice, William Joseph O‘Brien (1984), The Radio and Electronic Engineer, 54, 241.
4. Schwarz H.F.S. (1987). Early history of the Decca Navigator system, uncompleted paper in the Decca Archive held by author.
5. Atwell C. (1947). RAE tests of the Decca Navigator. RAE report, Feb 1947.