1. Alberda Th (1965) The influence of temperature, light intensity and nitrate concentration on dry-matter production and chemical composition ofLolium perenne L. Neth J Agric Sci 13, 335?360
2. Bartholomew PW and Chestnutt DMB (1977) The effect of a wide range of fertilizer nitrogen application rates and defoliation intervals on the dry-matter production, seasonal response to nitrogen, persistence and aspects of chemical composition of perennial ryegrass (Lolium perenne cv S 24). J Agric Sci Camb 88, 711?721
3. Behaeghe TJ and Carlier LA (1974) Influence of nitrogen levels on quality and yield of herbage under mowing and grazing conditions. Proc 5th Gen Meet Eur Grassl Fed Uppsala 1973, Växtodling 28, 52?66
4. Boer DJ den (1980) Nitraatgehaltes in gras en de gezondheid van weidend melkvee bij extreme stikstofbemesting. Stikstof No 95/96, 382?387
5. Burg PFJ van (1962) Interne stikstofbalans, produktie van droge stof en veroudering van gras. Versl Landbouwk Onderz 68-12, 131 pp