Salam, Abdul Kadir, et al. “Decrease in Activity of Acid Phosphatase in Root-Zones of Several Plants Driven by Lime and Lead-Containing Industrial Waste Treatments”. Jurnal Ilmu Tanah Dan Lingkungan, vol. 2, no. 1, Oct. 2009, pp. 1-6, https://doi.org/10.29244/jitl.2.1.1-6.