1. Galkin, A.A., Grinberg, O.Y., Dubinski, A.A., Kabdin, N.N., Krimov, V.N., Kurochkin, V.I., Lebedev, Y.S., Oranski, L.G., Shuvalov, V.F.: Prib. Techn. Exper. N4, 284 (1977)
2. Isaacs, N.A., Russel, D.K.: Rev. Scient. Instrum.57, 414–416 (1986)
3. Aurbuch, R.K., Richards, P.L.: Phys. Rev.B12, 2588–2595 (1975).
4. Kuroda, S., Motokawa, M.: J. Phys. Soc. Jap.44, 1797–1803 (1978)
5. Janssen, P., Mahy, M., Wolf, W.P.: Phys. Rev.B37, 4851–4863 (1988)