1. Bird Population Changes for the Years 1970–71
2. R. A. Dunning(1972 ). Seedling pests and diseases .Report of the Rothamsted Experimental Station for 1971, Part 1, p.271 .
3. R. A. Dunning(1973 ). Seedling pests .Report of the Rothamsted Experimental Station for 1972, Part 1, p.264 .