1. Schweizer, J., Tasset, F.: J. Phys. F 10 (1980) 2799.
2. Alameda, J.M., Givord, D., Lu, Q.: The Rare Earth in Modern Science and Technology, New York: Plenum Press, 1981, vol. 3, p. 399.
3. Lemaire, R., Schweizer, J.: J. Phys. (Paris) 28 (1967) 216.
4. Lemaire, R.: Cobalt 32 (1966) 132.
5. Kuijpers, F.A., Loopstra, B.O.: J. Phys. (Paris) 32 (1971) C1-656.