1. Ernst, R. R., Bodenhausen, G., and Wokaun, A. (1987) Principles of Nuclear Magnetic Resonance in One and Two Dimensions, Oxford University Press Oxford U.K.
2. Schmidt-Rohr, K., and Spiess, H. W. (1995), Multidimensional solid State NMR and Polymers, Academic Press 1994.
3. Brinkmann, D. (1992) Prog. NMR Spectrosc. 24, 527
4. Bjorkstam, J.L. and Villa, M. (1980) Magn. Reson. Rev. 6, 1.
5. Weigel M., Emond, M. H., DeBruin T.H.M., and Blasse, G. (1994), Chem. Mater. 6, 973.