Chu, Dayan, Yueqin Xie, Shenqiu Hong, Xiangyang Yan, Hongwu Tong, and Shaomin Liu. 2010. “Major Carotenoids in Tobacco Laminas: Identification and Quantification by HPLC With Photodiode Array Detection”. Asian Journal of Chemistry 22 (4):2635-47. https://asianpubs.org/index.php/ajchem/article/view/11455.