1. Bielek P 1968 Hydrothermic sensitivity of nitrate accumulation in soil.In Transactions XIII Congress of the International Society of Soil Science. Comm. II. Vol. II: 243, Hmb. W. Germany.
2. Bremner J M and Edwards A P 1965 Determination and isotope-ratio analysis of different forms of nitrogen in soils. I. Apparatus and procedure for distillation and determination of ammonium. Soil Sci. Soc. Amer. Proc. 29, 504–507.
3. Chesney H A D 1967 Denitrification, in some Trinidad soils. M. Sc. Thesis, Univ. West Indies, St. Augustine, Trinidad.
4. Cornforth I S and Davis J B 1968 Nitrogen transformation in tropical soils. I. Mineralization of nitrogen-rich organic materials added to soil. Trop. Agric. (Trin.) 45, 211–221.
5. Dalal R C 1975 Urease activity in some Trinidad soils. Soil Biol. Biochem. 7, 5–8.