1. Farming, Fertilizers and the Nitrate Problem;Addiscott,1991
2. Standard Methods for the Examination of Water and Wastewater;APHA,1985
3. El fósforo en los suelos españoles. V. Nuevo método para determiner el fósforo assimilable en los suelos;Burriel;An. Edaf. Fis. Veg.,1950
4. Acid minewater and agricultural pollution in a river skirting the Doñana National Park Guadiamar river, South West Spain;Cabrera;Water Res.,1984
5. Current status of research and technology concerning the problems posed by vegetation water;Fiestas Ros de Ursinos,1986