1. US 9.278.897 (2016 ExxonMobil); US 9.266.802 (2016 Chevron); US 9.249.066 (2016 Total); US 8.907.136 (2014 Dow); US 7.297.790 (2008 Sumitomo); US 7.323.576 (2008 Alphora); Lindström p.331;
2. Ertl/Knözinger/Weitkamp Vol. 5 p.2370;
3. Sheldon/van Bekkum‐4 p.295;