1. Adelberg, E.A., Mandel, M., and Chen, G.C.C. (1965). Biochem. Biophys. Res. Comm. 18, 788?795.
2. Cooper, G.F., and Van Horn, A.R. (1981). Tetrahedron Letters 22, 1479?1482.
3. Knight, J.C., and Wovcha, M.G. (1981). U.S. Patent 4304860.
4. Nakamatsu, T., Beppu, T., and Arima, K. (1983). Agric. Biol. Chem. 47, 1449?1454.
5. Schindler, J., and Schmid, R. (1982). Europatent 0061687.