1. Natürliches Verhalten—ein natürlicher Begriff;Algers;Berl. Münch. Tierärtzl. Wochenschr.,1992
2. Farming practices and adherence to an alternative-conventional paradigm;Allen;Rural Sociol.,1995
3. Does organic farming face distinctive livestock welfare issues?—A conceptual analysis;Alrøe;J. Agric. Environ. Ethics,2001
4. Andresen, N., 2000. The foraging pig—Resource utilisation, interaction, performance and behaviour of pigs in cropping systems. Dissertation. Agraria 227, Acta Univ. Agr. Sueciae, Uppsala. 40 pp.
5. Suffering animals in a green landscape?;Andrews;Dairy Farmer,1991