1. Optical and retinal factors affecting visual resolution;Campbell;J. Physiol., Lond.,1965
2. Application of Fourier analysis to the visibility of gratings;Campbell;J. Physiol., Lond.,1968
3. Application of Operational Amplifiers—3rd Generation Techniques;Graeme,1973
4. Frequency shifter for “howl” suppression;Hartley-Jones;Wireless World,1973
5. Shift phase independent of frequency;Shirley;Electronic Design,1970