1. J.B. Sills, 18th meeting S.E. Assoc. Game and Pish Commissioners, (1964), Clear water, Florida, U.S.A.
2. R.A. Grizzell, Jnr., 19th meeting S.E. Assoc. Game and Fish Commissioners, (1965), Tulsa, Oklahoma.
3. C.R. Walker, Weeds,13, (4), (1965).
4. H.G. Van der Weij, Proceedings 8th British Weed Control Conf., (3), 835–41, (1966).
5. S.E. Katz, J. Assoc. Offic. Agr. Chemists, 49, (2),452, (1966).