Li, Yang, Xin-Zhou Yang, Xeu-Sen Li, Fu-Quan Yao, and Qiu-Fen Hu. 2011. “Study on Solid Phase Extraction and Spectrophotometric Determination of Palladium With MCI GEL CHP 20Y As Sorbent”. Asian Journal of Chemistry 23 (11):4838-40. https://asianpubs.org/index.php/ajchem/article/view/10994.