1. S.K. Wong and J.K.S. Wan, J. Am. Chem. Soc., 94, 7197, (1972).
2. J.H. Freed and J.B. Pederson in: J.S. Waugh (Ed.), Adv. Magnetic Resonance, Academic Press, N.Y. 1976, vol. 8, p. 2.
3. F.J. Adrian, Res. Chem. Intermed., 3, 3, (1979).
4. K.A. McLauchlan in: L. Kevan and M.K. Bowman (Eds.), Modern Pulse and Continuous Wave Electron Spin Resonance, Wiley Interscience, N.Y. 1990, p. 285.
5. K.A. McLauchlan and F.J. Hore in: A.J. Hoff (Ed.), Advanced EPR: Applications in Biology and Biochemistry, Elsevier, Amsterdam, 1990, pp. 345.