He, Fen, et al. “Effects of Different Root Zone Heating Systems on Microclimate and Crop Development in Solar Greenhouses”. International Journal of Agricultural and Biological Engineering, vol. 15, no. 6, Dec. 2022, pp. 67-72, https://ijabe.migration.pkpps03.publicknowledgeproject.org/index.php/ijabe/article/view/7581.