1. General Cement Manufacturing Co., Rockford, Illinois.
2. Sigma Plastronics, Division of Grodan Manufacturing and Sales, 14531-33 Tireman Avenue, Dearborn, Michigan 48126.
3. J. L. Blankenship, C. J. Borkowski and R. J. Fox, Silicon surface barrier nuclear particle detectors, from a Conf. Nuclear electronics (Reference Number NE/136).
4. Ciba Products Corporation, Fairlawn, New Jersey.