VELUMANI, RAVI, et al. “Photosynthetic Response of Sweet Potato (Ipomoea Batatas) to Photon Flux Density and Elevated Carbon Dioxide”. The Indian Journal of Agricultural Sciences, vol. 87, no. 9, Sept. 2017, pp. 1231–1237, https://doi.org/10.56093/ijas.v87i9.74210.