1. for review see, e.g., The Metal Non-Metal Transition in Disordered Systems, eds. L.R. Friedman and D.P. Tunstall ( SUSSP Publ., Edinburgh 1978 ).
2. see, e.g., Anderson Localization, eds. T. Ando and H. Fukuyama, ( Springer, Berlin 1988 ).
3. for general properties of Mn-based semimagnetics see, e.g., Diluted Magnetic Semiconductors, volume eds. J.K. Furdyna and J. Kossut, in: Semiconductors and Semimetals, vol 25, series eds. R.K. Willardson and A.C. Beer ( Academic Press, Boston 1988 )
4. for review of transport properties see, J. Kossut, ibid. p. 183
5. N.B. Brandt and V.V. Moshchalkov, Adv. Phys.
33, 193 (1984)