Künzel, Wieland. (1989) 1989. Agroforestry in Tonga: A Traditional Source for Development of Sustainable Farming Systems. South Pacific Smallholder Project Occasional Paper No. 12. Armidale, NSW: University of New England; South Pacific Smallholder Project. http://www.worldcat.org/oclc/20746333.
coconuts
Nair, P. K. R., and Peter A. Huxley. (1983) 1983. “Agroforestry With Coconuts and Other Tropical Plantation Crops”. Plant Research and Agroforestry: Proceedings of a Consultative Meeting Held in Nairobi, 8 to 15 April 1981. Nairobi, Kenya: International Council for Research in Agroforestry. http://www.worldcat.org/oclc/11698847.