1. See e.g. Ultrafast Phenomena IX, P.F. Barbara, W.H. Knox, G.A. Mourou, and A.H. Zewail, Eds. (Springer-Verlag, Berlin Heidelberg, 1994) and previous Proceedings of the same series.
2. C.F. Klingshirn, Semiconductor Optics (Springer-Verlaf Berlin Heidelberg, 1995).
3. N. Peyghambarian, S.W. Koch, and A. Mysyrowicz, Introduction to Semiconductor Optics (Prentice Hall Inc., Englewood Cliffs, 1993).
4. D.L. Greenaway and G. Harbeke, Optical Properties and Band Structure of Semiconductors (Pergamon Press, Oxford, 1968).
5. E.O. Göbel and K. Ploog, Prog. Quant. Electr. 14, 289 (1990).