Categorising combinations of farmers' land use practices: an approach based on examples of sheep farms in the south of France Nathalie Girard, Stéphane Bellon, Bernard Hubert, Sylvie Lardon, Charles-Henri Moulin and Pierre-Louis Osty Agronomie, 21 5 (2001) 435-459 DOI: 10.1051/agro:2001136