1. Panayotou, T. & Ashton, P. Not by Timber Alone (Island, Washington DC, 1993).
2. Lampietti, J. A. & Dixon, J. A. To see the forest for the trees: a guide to non-timber forest benefits. Environment Department Paper No. 013 (The World Bank, Washington DC, 1995).
3. Chomitz, K. M. & Kumari, K. The domestic benefits of tropical forests: A critical review. World Bank Obs. 13, 13–35 (1998).
4. Costanza, R. et al. The value of the world's ecosystem services and natural capital. Nature 387, 253–260 (1997).
5. Kumari, K. An environmental and economic assessment of forest management options: a case study in malaysia. Environmental Economic Series Paper No. 026 (The World Bank, Washington DC, 1995).