1. R.S. Alger, Electron Paramagnetic resonance: Techniques and Applications, 2nd edn., (John Wiley & Sons Inc., Joboken, 1968)
2. C.P. Poole Jr, Electron spin resonance, 2nd edn., (Dover Publications Inc., New York, 1983)
3. C.P. Slichter, Principles of Magnetic Resonance with Example from Solid State Physics, (Harper&Row Publications Inc., New York, 1963)
4. B. Cowan, Nuclear Magnetic Resonance and Relaxation, (Cambridge University Press, Cambridge, 1997)
5. J.H. Ardenkjæ-Larsen, B. Fridlund, A. Gram, G. Hansson, L. Hansson, M.H. Lerche, R. Servin, M. Thaning, K. Golman, PNAS, 100, 18 (2003), pp. 10158-10163,
https://doi.org/10.1073/pnas.1733835100