1. Carey I 1976. Orang Ash: The Aboriginal Tribes of Peninsular Malaysia. Kuala Lumpur: Oxford University Press.
2. Dentan RK 1979. The Semai: A Nonviolent People of Malaya. Chicago: Holt, Rinehart and Winston, Inc.
3. Dentan RK, Ong HC 1995. Stewards of the green and beautiful world: A preliminary report on semai arboriculture and its policy implications. In: R Talib, C B Tan (Eds.): Dimensions of Traditions and Development in Malaysia. Kuala Lumpur: Pelanduk Publications, pp. 53-124.
4. Henderson MR 1974. Malayan Wild Flowers. 2 Volumes. Kuala Lumpur: Malayan Nature Society.
5. Ng F SP 1995. Tree Flora of Malaya. Volumes 3 and 4. Kuala Lumpur: Longman.