MESOSCOPIC TUNNELING IN DISORDERED MAGNETIC SYSTEMS : A COMPARISON WITH MACROSCOPIC TUNNELING IN SQUIDS B. Barbara, P. C. E. Stamp et M. Uehara J. Phys. Colloques, 49 C8 (1988) C8-529-C2-530 DOI: 10.1051/jphyscol:19888240