| Chemical Abstracts, 85:21185j (1976), [Buza, D. et al., Rocz. Chem. 1975, 49(12), 2001-16]. |
| Hurtley, W. et al., J. Chem. Soc., pp. 1821-1828 (1926). |
| Hunig, S., et al., Liebigs Ann. Chem., 738, 192-194 (1970). |
| Dallacker, F., et al., Liebigs Ann. Chem., 689, 179-183 (1965). |
| Shasha, B., et al., Nature, 210 (No. 5031), 89-90 (1966). |
| Chemical Abstracts, 60:5665-7 (1964), [Wizinger, I. et al., Helv. Chim. Acta, 46(6), 2167-7 (1963)]. |
| Chemical Abstracts, 78:16155a (1973), [Feher, F., et al., Z. Naturforsch. B 1972, 27(8), 1006-7]. |