References
- J. B. D. Robinson; W. G. Dyson; P. J. Dickinson; P. Howland and G. Semb (1969). The efficiency of Muguga Standard potting soil. E. Afr. agric. For. J. 35: 68–77.
- Fisher Electrophotometer II—Instruction manual. Fisher Scientific, Pittsburgh. P.A.
- W. E. Looms and C. A. Schull, (1937). Methods in plant physiology. A laboratory manual and Research handbook. Macgraw-Hill Book Company Inc.