1. S. D. Slobin, “A Study of Asymmetrical Cassegrain Antenna Feed System Applications to Millimeter Wavelength Radio Astronomical Problems,” USC EE Report 321, University of Southern California, Electrical Science Lab, Dec. 1968.
2. National Aeronautic and Space Administration, US Patent no. 3,417,399, “Millimeter Wave Radiometer for Radio Astronomy” 17 Dec. 1968.