1. W. Barth, N. Fessler-Wilhelmi, W. Lehman, and P. Turowski, in Advances in Cryogenic Engineerings Vol, 25, Plenum Press, New York (1980), p. 163.
2. “Proposal for a 4π Magnetic Detector for PETRA,” prepared by Desy, Karlsruhe, München, Orsay, Paris, and Saclay (July 1976).
3. H. Desportes, in Proc. 6th Intern. Conference on Magnet Technology, ALFA, Bratislava Czechoslovakia (1977), p. 474.
4. P. Genevey and J. Le Bars, in Proc. 6th Intern. Conference on Magnet Technology, ALFA Bratislava Czechoslovakia (1977), p. 1093.
5. W. V. Hassenzahl, in Advances in Cryogenic Engineering, Vol. 25, Plenum Press, New York (1980), p. 185.