1. 2. N.A.A.S. AnonUnpublished data.
2. 3. Anon., 1962 .Great House Experimental Husb. Farm Review, Min. of Agric. Fish. and Food.
3. 4. Anon. 1963 . A.R.C. Symposium on Grassland Improvement, Oxford-January 1963.
4. 5. Anon., 1963 , Better grass without the plough .Fmr's Wkly, Lond. 14.6.63p.45 .