1. Britton, R. B., Proc. 1968 Summer Study Supercond. Devices and Accelerators, Brookhaven National. Laboratory, BNL. 50155, p. 449, 1968.
2. Stekly, Z. J. J., Journal of Applied Physics Vol. 42, No. 1, p. 65, Jan. 1971.
3. Stekly, Z. J. J., et al., BNL 50155, p. 748.
4. Gauster, W. F., and Hendricks, J.B., Journal of Applied Physics Vol. 39, p. 2572, 1968.
5. Maddock, B. J., et al. Cryogenics, Vol. 9, No. 4, p. 261, August, 1969.