1. A.Lösche, Some NMR Investigations of Liquid Crystals, Proc.XVIB, Congress Ampere 1972, pp.101–117.
2. . A.Pines, M.G.Gibby, J.S.Waugh, J.Chem.Phys. 56 (1972) 1776, 59 (1973) 569
3. We are grateful to Prof.Schneider, TH Leuna-Merseburg, for trg permission to use their spectrometer Bruker SXP.
4. A.Lösche, Ann.Phys. (7) 31 (1974) 182.
5. St.Limmer, private communication;