Boyd, D. A., Church, B. M., Hills, M. G. and Heafield, T. G. 1966. Types of fertilizers used on farm crops in England and Wales. NAAS Quarterly Review.
Broadbent, L., Burt, P. E. and Nix, J. S. 1957. The cost of using insecticides to maintain the health of potato seed in England and Wales. NAAS Quarterly Review. 38 (Winter), pp. 144-153.