1. R. Sachs, Phys. Rev.,128, 2851 (1962).
2. A. Komar, Phys. Rev. B,134, 1430 (1964).
3. I. V. Volovich, V. A. Zagrebnov, and V. P. Frolov, Fiz. Elem Chastits At. Yadra,9, 10 (1978).
4. A. I. Oksak, Teor. Mat. Fiz.,48 297 (1981).
5. F. A. Lunev, ?Canonical quantization on the light cone. I. Scalar field,? Preprint 81-74 [in Russian], Institute of High Energy Physics, Serpukhov (1981).