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2. Buyers, W.J.L.: Magnetism and Magnetic Materials, AIP Conf. Proc.24, 27 (1975)
3. Fulde, P.: Z. Physik B20, 89 (1975)
4. Bucher, E., Dernier, P.D., Maita, J.P., Longinotti, L.D., Lüthi, B., Wang, P.S.: Magnetism and Magnetic Materials, AIP Conf., Proc.24, 241 (1975)
5. Junod, P., Menth, A., Vogt, O.: Phys. Kond. Materie8, 323 (1969)