POSITION AND CHARACTER (Ɖ OR X) OF ENERGY STATES IN SHORT-PERIOD (GaAs)m(AlAs)n SUPERLATTICES J. NAGLE, M. GARRIGA, W. STOLZ, T. ISU and K. PLOOG J. Phys. Colloques, 48 C5 (1987) C5-495-C5-498 DOI: 10.1051/jphyscol:19875105