1. ANDERSON L. J. and SEVEL T. (1975) Six years' environmental Tritium profiles in the unsaturated and saturated zones, Gronhoj, Denmark. Proc. Symp. “Isotope Hydrology” IAEA, Vienna. 3–20.
2. Nitrous oxide in the atmosphere of a red brown earth;BURFORD;Trans. 9th Int. Congr. Soil Sci.,1968
3. Fertilizer practice in England and Wales: a new series of surveys;CHRUCH;J. Sci. Ed. Agric.,1971
4. losses of nitrogen and phosphorus from agricultural, land;COOKE;Water Treat. Exam.,1970
5. DAVEY K. W. (1970) An investigation into the nitrate pollution of chalk borehole water sulies. North Lindsey Water Board, Scunthorpe.