1. Seydel, J. K., Z. Naturforsch. 16b, 419 (1961).
2. Kakimoto, S., Seydel, J.K. and Wempe, E., Arzneimittel-Forsch. 12, 127 (1962).
3. Pappalardo, G., Tornetta, B., Condorelli, P. and Bernardini, A., Farmaco, Ed. Sci. 22, 808 (1967).
4. Walter W. and Voss J., in: The Chemistry of Thioamides, (Ed. Zabicky J.) p. 412, John Wiley and Sons (Interscience Publishers), London (1970).
5. Mehlborn, A. and Fabian, J., Z. Chem. 5, 420 (1965).