Jianfeng, Wang, He Dongxian, Song Jinxiu, Dou Haijie, and Du Weifen. 2015. “Non-Destructive Measurement of Chlorophyll in Tomato Leaves Using Spectral Transmittance”. International Journal of Agricultural and Biological Engineering 8 (5). Beijing, China:73-78. https://ijabe.org/index.php/ijabe/article/view/1931.