NONLINEAR OPTICAL EFFECTS AT THE FUNDAMENTAL ABSORPTION-EDGE OF WIDE-GAP II-VI SEMICONDUCTORS F. HENNEBERGER, J. PULS, H. ROSSMANN, M. KRETZSCHMAR, C. SPIEGELBERG and A. SCHÜLZGEN J. Phys. Colloques, 49 C2 (1988) C2-91-C2-96 DOI: 10.1051/jphyscol:1988220