Petcov THREE-NEUTRINO OSCILLATIONS IN THE EARTH: RESONANCE AMPLIFICATION AND T-VIOLATION EFFECTS .......................... 145 A. E. Chudakov VHE AND UHE GAMMA RAY ASTRONOMY: HISTORY AND PROBLEMS .............. 163 G. B. Yodh ULTRA HIGH ENERGY ASTRONOMY ........................................ 183 A. E. Chudakov, G. Navarra and V. A. Tizengauzen ON THE 100 TeV UHE GAMMA-RAY DATA FROM CYGNUS X-3 AND HERCULES X-1 IN 1986 ....................................... 211 G. B.