DOUBLE UNSATURATED HeII BATHS FOR NESTING SUPERCONDUCTING SOLENOIDS PRODUCING FIELDS GREATER THAN 14 T G. Faure-Brac, A.S. Greenberg, B. Hébral et J.C. Vallier J. Phys. Colloques, 45 C1 (1984) C1-75-C1-78 DOI: 10.1051/jphyscol:1984116