9Obrucheva N V. The relationship between root growth and synthesis of secondary components structrue and function of primary root-tissues. Proceedings of A Symposium.Tatranska, lommica, September 7- 10,1971.
10Patel N M. Correlation analysis in studying influnce of root growth in yield and qulity of Bidi tobacco. Tobacco Res. ,1988,14:25~27.