[1] Kane E O 1957 Phys. Chem. Solids 1 249

[2] Askerov B M 1994 Electron Transport Phenomena in
Semiconductors (Singapore: World Scientific) p 15

[3] Filatov O N and Karpovic I A 1968 Fizika Tvyordoqo Tela. Sov.
J. 10 2886

[4] Filatov O N, Karpovic I A 1969 Pisma v Jurnal Exper. iTeoret.
Fiziki. Sov. J. 10 224

[5] Ekenberg U 1989 Phys. Rev. B 40 7714

[6] Warburton R J, Michels J G, Nicholas R J, Harris J J and Foxon C T
1992 Phys. Rev. B. 46 20 13394

[7] Huant S, Mandray A, Etienne B 1992 Phys. Rev. B 46 2613

[8] Kotera N, Arimoto H, Miura N, Tanaka K, Kawano T, Shibata K,
Nakamura H, Mishima T, Aiki K and Washima M 2001 Physica B
298 221

[9] Kotera N, Arimoto H, Miura N, Shibata K, Ueki Y, Tanaka K, Nakamura
H, Mishima T, Aiki K and Washima M 2001 Physica E 11 219