1. Traverse, A., Bernas, H., Chaumont, J., Dumoulin, L., Gupta, M.: Solid State Commun. 40 (1981) 725.
2. Umbach, C.P., Toth, L.E., Dahlberg, E.D., Goldman, A.M.: LT-16, Vol.2 (1981) 803.
3. Van Dongen, J.C.M., Van Dijk, D., Mydosh, J.A.: Phys. Rev. B24 (1981) 5110.
4. Van Haesendonck, C., van den dries, L., Bruynseraede, Y., Gilabert, A.: IEEE Trans. Magn. 17 (1981) 777.
5. Vining, C.B., Shelton, R.N.: Ternary Superconductors, Shenoy, G.K., Dunlap, B.D., Fradin, F.Y. (eds.), New York: North Holland, 1981, p. 189.