REVIEW OF NEW MATERIALS FOR THE GENERATION OF VERY LOW TEMPERATURES BY HYPERFINE ENHANCED NUCLEAR ADIABATIC COOLING E. BUCHER, K. ANDRES, J. P. MAITA, A. S. COOPER et L. D. LONGINOTTI J. Phys. Colloques, 32 C1 (1971) C1-114-C1-116 DOI: 10.1051/jphyscol:1971136