1. Alder LH, Roessler E (1972) Introduction to probability and statistics. W.H. Freeman and Company, New York, p 373
2. de Groot RS, Stuip MAM, Finlayson CM, Davidson N (2006) Valuing wet-lands: guidance for valuing the benefits derived from wetland ecosystem services, Ramsar Technical Report No. 3/CBD Technical Series No. 27. Ramsar Convention Secretariat, Gland, Switzerland and Secretariat of the Convention on Biological Diversity, Montreal, Canada
3. Holmes J (1995) Natural forest hand book for Tanzania: forest ecology and management vol I, chapter 5. Sokoine University of Agriculture, Faculty of Forestry, Morogroro, Tanzania, pp 395–416
4. Intergovernmental Panel on Climate Change (2001) Climate change 2001 synthesis report. Cambridge University Press, Cambridge, MA
5. Jackson IJ (1971b) Atmospheric pressure and winds, rainfall in Tanzania in maps. University of London Press; pp 34–39. Cited in Nshubemuki L, Somi FGR, Olotu C. A forester’s view on average monthly and annual rainfall and number of rain days over Tanzania—regional comparisons. Tanzania Silviculture Technical Note. No. 41; 1978