1. Knots;Burde,1985
2. P. J. Freyd, unpublished lectures, Milan and Cambridge, summer 1986.
3. A new polynomial invariant of knots and links;Freyd;Bull. Amer. Math. Soc.,1985
4. A polynomial invariant of knots via Von Neumann algebras;Jones;Bull. Amer. Math. Soc.,1985
5. A. Joyal and R. Street, Braided monoidal categories, preprint.