INITIAL SLOPE OF THE HYSTERESIS CURVE G. J. Gerritsma, M. T. H. C. W. Stam, J. C. Lodder and Th. J. A. Popma J. Phys. Colloques, 49 C8 (1988) C8-1997-C8-1998 DOI: 10.1051/jphyscol:19888906
