K Sireesha, B. T. P. P. R. D. “Betel Leaf Yield in Relation to Soil Fertility in Guntur District (Andhra Pradesh)”. Journal of Spices and Aromatic Crops, vol. 22, no. 1, June 2013, pp. 62-64, https://www.updatepublishing.com/journal/index.php/josac/article/view/5035.