1. US 7.655.821 (2008 Lubrizol); US 6.137.269 (2001 UCC); US 5.502.243 (1996 Air Prod.); US 5.198.577 (1993 Rhone‐Poulenc); US 5.962.744 (1995 Mitsubishi); US 4.482.748 (1984 Celanese); US 3.965.192 (1976 Union Oil); US 5.744.636 (1998 Air Prod.); Falbe‐1 p.250;
2. Moser/Slocum p.283;
3. Sen p.174;