YBa2Cu3O7-δ SINGLE CRYSTALS INVESTIGATED BY TORQUE AND MAGNETOMETRY L. Fruchter, C. Giovannella, M. Ousséna, S. Senoussi and I. A. Campbell J. Phys. Colloques, 49 C8 (1988) C8-2181-C8-2182 DOI: 10.1051/jphyscol:19888978