1. A plant DNA minipreparation: Version II
2. M. D. Gupta , 1987 : Inheritance of powdery mildew resistance in pea (Pisum sativumL.). PhD Thesis . Indian Agricultural Research Institute, New Delhi, India.
3. FAO , 1966 , 1966 , 1966 , 1966 : FAO Production Yearbooks 20 , 20 , 20 , 20 , Table 34. Rome, Italy.
4. FAO , 2001 : FAO Bulletin of Statistics 2 , Table 24.