1. Abbozzo, P., Mennella, V.: 1993, L'impatto delle agrotecnologie nel Bacino del Tevere. Criteri per la valutazione di impatto ambientale, Franco Angeli, Milano.
2. Cantrell, J.: 1985, A low investment swine system: a demonstration project, Kerr Fundation, Oklahoma.
3. Carnell, P.: 1983, Alternatives to factory farming. Earth Research LTD, London.
4. Curtis S.E.: 1983, Environmental management in animal agriculture, Iowa State University Press.
5. Edelman M.A.: 1994, Hog confinement policy issues and options, Dept. of Economics, Iowa State University, Staff paper 252.