1. See, e.g., Ramirez, A.P., Schneemeyer, L.F., Warszcak, J.V.: Phys. Rev. B36, 7145 (1987)
2. See, e.g., Seaman, C.L., Ayoub, N.Y., Bjornholm, T., Early, E.A., Gharmaty, S., Lee, B.W., Markert, J.T., Neumeier, J.J., Tsai, P.K., Maple, M.B.: Physica C159, 391 (1989)
3. See, e.g., Yang, K.N., Dalichaouch, Y., Ferreira, J.M., Lee, W.B., Neumeier, J.J., Torikachvili, M.S., Zhon, H., Maple, M.B., Hake, R.R.: Solid State Commun.63, 518 (1987)
4. Furrer, A., Allenspach, P., Mesot, J., Staub, U., Blank, H., Mutka, H., Vettier, C., Kalids, E., Karpinski, J., Rusiecki, S., Mirmelstein, A.: Eur. J. Solid State Inorg. Chem.28, 627 (1991)
5. Furrer, A., Allenspach, P., Mesot, J., Staub, U.: Physica C168, 609 (1990)