Idris, A. et al. 2018. Effect of Light on the Photosynthesis, Pigment Content and Stomatal Density of Sun and Shade Leaves of Vernonia Amygdalina. International Journal of Engineering & Technology. 7, 4.30 (Nov. 2018), 209–212. DOI:https://doi.org/10.14419/ijet.v7i4.30.22122.