1. Camley, R.E., Stamps, R.L.: J. Phys. 5, 3727 (1993)
2. Shaulov, G., Seidov, Y.: J. Magn. Magn. Mater. 527, 140 (1995)
3. Balcerzak, T., Tucker, J.W.: J. Magn. Magn. Mater. 653, 140 (1995)
4. Hai, T., Li, Z.V., Lin, D.L., George, T.F.: J. Magn. Magn. Mater. 227, 97 (1991)
5. Aguilera-Granaja, F., Moran-Lopez, J.L.: Solid State Commun. 47, 155 (1990)