“Nickel (II) And Lead (II) Removal from Aqueous Solution Using Immobilized Lonchocarpus Laxiflorus, Barkstem As an Adsorbent”. Jewel Journal of Scientific Research, vol. 3, no. 1, Dec. 2015, pp. 62-72, https://jjsr.org/index.php/jjsr/article/view/189.