1. Anderson JM, Ingram JSI (1998) Nitrogen. In: Chapter 6, Tropical soil biology and fertility: a handbook of methods, 2nd edition. CAB International, Wallingford, UK, pp. 70–75
2. Anonymous (2000) Topical issue: Frost damage report west of Rift. TRFK Q Bull 5:3–7
3. Anonymous (2004) Country programme action plan, 2004–2008, Government of Kenya and the United Nations development programme report, pp. 54
4. Brown S (1997) Estimating biomass and biomass change of tropical forest: a primer. FAO forestry paper no. 134, Food and Agriculture Organization, Rome, Italy
5. Burgess PJ, Sanga BNK (1994) Dry weight and root distribution of mature tea. Ngwazi Tea Research Unit Quarterly Report 16:14–18