| Chemical Abstract No. 72:45141, which is an abstract of Finland Patent Specification No. 37218 (Feb. 1969). |
| Chemical Abstract No. 87-278790, which is an abstract of German Patent Sepcification No. 3,610,374 (Oct. 1987). |
| Chemical Abstract No. 91:118691, which is an abstract of French Patent Specification No. 2,392,787 (Dec. 1978). |
| Chemical Abstract No. 95:171338, which is an abstract of German Patent Specification No. 3,004,248 (Aug. 1981). |
| WPIDS abstract No. 72-68779T, which is an abstract of Soviet Union Patent Specification No. 326204 (Jan. 1972). |