Johnson K George, N K Leela, P A Mathew, P Utpala, G R Asish, K V Saji,. 2014. “Diversity Study of Leaf Volatile Oil Constituent of Piper Species Based on GC/ MS and Spatial Distribution”. Journal of Spices and Aromatic Crops 23 (1):10-16. https://updatepublishing.com/journal/index.php/josac/article/view/5077.