Lawal, I., and A. Isichei. “AN ASSESSMENT OF HEAVY METAL CONTENT OF ROADSIDE VEGETATION ALONG TWO MAJOR HIGHWAYS IN THE SOUTHWESTERN NIGERIA”. LAUTECH Journal of Engineering and Technology, Vol. 8, no. 2, Aug. 2014, pp. 24-29, https://laujet.com/index.php/laujet/article/view/116.