1. Y. Cho et al, Argonne National Laboratory; B. Brabson et al., Indiana University; C. Akerlof et al, University of Michigan; D. Buchholz et al., Northwestern University; R. Mcllwain et al., Purdue University; “Proposal for a PEP Spectrometer Facility,” December 31, 1976.
2. S. H. Kim and S. T. Wang, in: Advances in Cryogenic Engineering, Vol. 24, Plenum Press, New York (1978).