1. Atherton H. W., Nuclear Physics B103 (1976), 381.
2. Cvach J., Chýla J., Czech. J. Phys. B27(1977), 1315
3. Chýla J., Thesis, unpublished, FZÚ 1977.
4. Gall P. -D., Thesis, DESY Report F1-76/02.
5. Boos E. G., et al., Nuclear Physics B121 (1977), 381.