Ting, Li, et al. “Universality of an Improved Photosynthesis Prediction Model Based on PSO-SVM at All Growth Stages of Tomato”. International Journal of Agricultural and Biological Engineering, vol. 10, no. 2, Mar. 2017, pp. 63-73, https://ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/2580.