1. G. Fischer, unpublished results (1963).
2. The Chemistry of 1,2-Dithiole-3-thiones
3. L. Bülling, J. Faust, M. Fischer, S. Gahler, J. Jentzsch, and R. Mayer, DDR Pat. 54,187 (1967) [CA 67 77879(1967)].
4. G. Fischer, unpublished results (1968–1976).
5. S. Giese, Thesis Technische Universität Dresden (1976).