1. Perturbative Quantum Chromodynamics, edited byA. Mueller (World Scientific, Singapore, 1987).
2. J. D. Bjorken: inProceedings of III International Symposium on Electron and Photon Interactions, Standford, California, 1967;R. P. Feynman:Phys. Rev. Lett.,23, 1415 (1969).
3. S. M. Troshin andN. E. Tyurin:Int. J. Mod. Phys. A,5, 2689 (1990).
4. A. Manohar andH. Georgi:Nucl. Phys. B,234, 139 (1984).
5. F. Close:An Introduction to Quarks and Partons (Academic Press, London, 1979);L. Pondrom:Invited talk given at the VII International Symposium on High Energy Spin Physics, Protvino, Russia, September 1986.