PROPAGATION EFFECTS AND OPTICAL NONLINEARITIES OF EXCITONS IN MULTIPLE QUANTUM-WELLS J.A. LEVENSON, R.K. RAJ, I. ABRAM, G. DOLIQUE et F. ALEXANDRE J. Phys. Colloques, 48 C5 (1987) C5-541-C5-544 DOI: 10.1051/jphyscol:19875116