1. Bleasdale, J. K. A., andRoberts, H. A. (1957). Some preliminary observations on the assessment of weed control in row crops. Proc. Brit. Weed Control Conf., 1956, 651.
2. Ministry of Agriculture and Fisheries(1951). Marketing Guide No. 5. Min. Agric. Fish. Marketing Div., Lond.
3. Ministry of Agriculture and Fisheries(1954). Marketing Guide No. 4. Min. Agric. Fish. Marketing Div., Lond.
4. Rubio, J. I. E., Winter, E. J., andStanhill, G. (1957). The weather during 1956. Rep. Nat. Yeg. Res. Sta. Wellesbourne for 1956, 71.
5. Rubio, J. I. E., Winter, E. J., andStanhill, G. (1958). The weather during 1957. Rep. Nat. Veg. Res. Sta. Wellesbourne for 1957, 58.