1. W. O. Haag and D. D. Whitehurst: German Patent1,800,371 (1969); Chem. Abs. 71, 114951 (1969)
2. W. O. Haag and D. D. Whitehurst: German Patent1,800,379 (1969); Chem. Abs. 72, 31192 (1970)
3. W. O. Haag and D. D. Whitehurst: German Patent1,800,380 (1969); Chem. Abs. 71, 33823 (1969)
4. W. O. Haag and D. D. Whitehurst: Belgian Patent721, 686 (1969)
5. W. O. Haag and D. D. Whitehurst: Proc. 2nd North Amer. Meeting Catal. Soc. 16 (1971)