1. 13. Madden P. 1987b. Economic evaluation of alternative farming practices and systems. Unpublished draft.
2. 14. Papendick R. 1984. Alternative agriculture systems: Benefits to soil and water resources. Proceedings of the Institute for Alternative Agriculture First Annual Scientific Symposium. Institute for Alternative Agriculture, Greenbelt, Maryland, pp. 3–4.
3. An economic analysis of alternative cropping systems for east-central Nebraska;Helmers;American Journal of Alternative Agriculture,1986
4. The transition to organic agriculture: A multi-year simulation of a Pennsylvania farm;Dabbert;American Journal of Alternative Agriculture,1986