International Conference on Solid State Nuclear Track Detectors 9th Munich 1976. International Conference on solid State Nuclear Track Detectors 10th Lyon 1979. International Conference on Solid State Nuclear Track Detectors 10th Lyon 1979 International Conference on Cyclotrons and theiry Applications 7th Zurich 1975 International Conference on The Physics of Semicon Ductors 13th Rome 1976. International Conference on Amorphous and liquid Semiconductors 7th Edinburgh 1977 International Conference on Advanced Infrared Detectors and Systems International Congress on Medicinal Plant Research,Munich,1976. International conference on high energy accelerators.1961 International Conference on Communications,Boston 1979.