1. 1) FAO: Revised Legend of the FAO-UNESCO Soil Map of the World (World Soil Resources Report No. 60, Rome, 1988), p. 109.
2. 2) Subagjo and P.M. Driessen: The Ombrogenous Peats in Indonesia. Research Papers 1968-1974 (Agr. Coop. Indonesia /The Netherlands, 1974), pp. 193-205.
3. Indonesian peat swamp forests and their role as a carbon sink
4. Hydrology and peat-land development in Indonesia
5. 5) B. Polak: Proceedings of the 4th International Congress of Soil Science 2 (1950), pp. 183-185.