1. Borel R (1987) Agroforestry systems interactions: man-tree-crop-animal. In: Beer J, Fassbender HW and Heuveldop J, eds, Advances in Agroforestry Research, pp 104?121. Proceedings. CATIE, Turrialba, Costa Rica
2. Borel R and Romero F (1991) On-farm research in a silvopastoral project: a case study. Agroforestry Systems 15: 245?257
3. Budowski G (1987a) The development of agroforestry in Central America. In: Steppler HA and Nair PKR, eds, Agroforestry: A Decade of Development, pp 69?88. ICRAF, Nairobi, Kenya
4. Budowski G (1987b) Living fences in Tropical America: a widespread agroforestry practice. In: Gholz HL, ed, Agroforestry, Realities, Possibilities and Potentials, pp 169?178. Martinus Nijhoff, Dordrecht, The Netherlands
5. Combe S and Gewald N, eds (1979) Guía de campo de los ensayos forestales del CATIE en Turrialba, Costa Rica. CATIE, Programa de Recursos Naturales Renovables. Turrialba, Costa Rica, 378 pp