1. T. Orth, U. Netzelmann, J. Pelzl, Appl. Phys. Lett. 53, 1979 (1988)
2. J.A. Romano, A.M. Mansanares, E.C. da Silva, H. Vargas, J. Phys. IV, C7-667 (1994)
3. R. Meckenstock, D. Spodding, J. Pelzl, J. Magn. Mater. 240, 83 (2002)
4. C.P. Poole Jr., Electron Spin Resonance (Wiley, New York, 1983)
5. A. Abragam, B. Bleaney, Electron Paramagnetic Resonance of Transition Ions (Dover, New York, 1986)