<center>'''Sources of literature of the Exudates volume'''</center>
<center>for minor species</center>
* 23. Heyne, K., 1927. De nuttige planten van Nederlands Indië [The useful plants of the Dutch East Indies]. 2nd Edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch Indië. 1953 pp. (3rd Edition, 1950. van Hoeve, 's Gravenhage, the Netherlands / Bandung, Indonesia. 1660 pp.).
* 24. Hooker, J.D., 1872-1897. The flora of British India. 7 Volumes. L. Reeve & Co., London, United Kingdom.
* 25. Howes, F.N, 1949. Vegetable gums and resins. Chronica Botanica Company, Waltham, Massachusetts, United States. 188 pp.
* 26. Hsuan Keng, 1990. The concise flora of Singapore. Gymnosperms and dicotyledons. Singapore University Press, Singapore. 222 pp.
* 27. Jumelle, H., 1903. Les plantes à caoutchouc et à gutta. Exploitation, culture et commerce dans tous les pays chauds [The rubber and gutta-producing plants. Exploitation, cultivation and trade in all warm countries]. A. Challamel, Paris, France. 543 pp.