1. CTRI-Rajahmundry (2015) Tobacco in Indian economy.
http://www.ctri.org.in/fortobaccoEconomy.php
2. China Tobacco Corporation (1992) Training handbook of Chinese grading criteria of flue-cured tobacco leaves. China Standards Publishing House, Beijing, pp 1–38
3. United States Department of Agriculture Official Standard Grades for Flue-Cured Tobacco (1989) U.S. Types 11, 12, 13, 14, and Foreign Type 92, 27 March 1989
4. Zhang J et al (1997) A trainable grading system for tobacco leaves. Comput Electron Agric 16(3):231–244
5. Han L (2008) Recognition of the part of growth of fluecured tobacco leaves based on support vector machine. In: Intelligent Control and Automation, WCICA 2008. IEEE 7th World Congress on 2008, pp 3624–3627