Ee, G.C.L., S.K. Lim, C.M. Lim, and K. Dzulkefly. “Alkaloids and Carboxylic Acids from Piper Nigrum”. Asian Journal of Chemistry 20, no. 8 (March 30, 2010): 5931–5940. Accessed July 16, 2024. https://asianpubs.org/index.php/ajchem/article/view/13041.