VALENCE BAND STRUCTURE OF STRAINED-LAYER Si-Si0.5Ge0.5 SUPERLATTICES U. EKENBERG, W. BATTY and E.P. O'REILLY J. Phys. Colloques, 48 C5 (1987) C5-553-C5-556 DOI: 10.1051/jphyscol:19875119