1. The Bible, Exodus 23
2. Haarmann W (1877) Kaiserliches Patentamt no 576
3. Rabenhorst J, Hopp R (1991) DE 3 920 039
4. Rabenhorst J, Hopp R (1997) EP 0 761 817
5. Shaikh Y (2002) Specialty Aroma Chemicals in Flavors and Fragrances. Allured, Carol Stream, p vii