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2. W. Ott, K. Freudenberger, F. Probst, F.P. Penningsfeld, R. Süss, to be published.
3. Plasma Surface Interactions in Controlled Fusion Devices (Report on the Third International Conference, Culham, 1978)
4. Ormak system beam impurities;Stewart,1972
5. S. Tanaka et al., 9th Symp. on Engin. Problems of Fusion Research, Chicago, Ill, USA, Oct. 1981, paper 5D-03.