1. Black (1953) Chem Soc Ann Reps p 332
2. Steiner, McNeely (1954) Am Chem Soc Advances in Chemistry Series 11: 72
3. Baardseth E (1966) Proc 5th Int Seaweed Symp, p 19
4. Baardseth E (1968) Proc 6th Int Seaweed Symp, p 53
5. Smidsrod 0, Haug A (1959) Acta Chem Scand 13 :1250