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2. N.P. Warner, Lectures on N = 2 superconformai theories and singularity theory”, in “Superstrings ′89,” proceedings of the Trieste Spring School, 3–14 April 1989. Editors: M. Green, R. Iengo, S. Randjbar-Daemi, E. Sezgin and A. Strominger. World Scientific (1990); “N = 2 Super symmetric Integrable Models and Topological Field Theories,” Lectures given at the Summer School on High Energy Physics and Cosmology, Trieste, Italy, June 15th–July 3rd, 1992. To appear in the proceedings.
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