1. See, e.g.: Weil JA, Bolton JR (1994) Electron paramagnetic resonance: elementary theory and practical applications. Wiley, New York
2. Weltner W Jr (1983) Magnetic atoms and molecules. Van Nostrand, New York
3. Harriman JE (1978) Theoretical foundations of electron spin resonance. Academic, New York
4. Möbius K (1993) In: Berliner LJ, Reuben J (eds) Biological magnetic resonance, vol 13. Plenum Press, New York, pp 253–274
5. Prisner TF (1997) In: Warren W (ed) Advances in magnetic and optical resonance, vol 20. Academic, New York, pp 245–299