1. Bonnieux, F. and P. Rainelli (1988), ?Agricultural Policy and Environment in Developed Countries?, European Review of Agricultural Economics 15(2/3), 263?281.
2. Brown, R. S. and L. R. Christensen (1981), ?Estimating Elasticities of Subsitution in a Model of Partial Static Equilibrium: An Application to U.S. Agriculture, 1947 to 1974?, in Berndt and Field (eds.), Modelling and Measuring Natural Resource Substitution.
3. Chambers, R. G. (1988), Applied Production Analysis ? A Dual Approach, Cambridge University Press.
4. COM (88) 708, Proposition de directive du Conseil concernant la protection des eaux douces côtières et marines contre la pollution des nitrates à partir de sources diffuses. Commission des Communautés Européennes.
5. Avebury Studies in Green Research;J. Conrad,1990