Masahiko Katoh, Satoshi Masaki, and Takeshi Sato. “Single-Step Extraction to Determine Soluble Lead Levels in Soil”. GEOMATE Journal 3, no. 6 (December 31, 2012): 375–380. Accessed May 3, 2024. https://geomatejournal.com/geomate/article/view/1645.