Zhang, Peng-Fei, Hong-Wen Gao, and Nai-Kui Shen. 2010. “Determination of Germanium With Phenylfluorone by Β-Correction Sectrophotometry ”. Asian Journal of Chemistry 10 (4):767-70. https://asianpubs.org/index.php/ajchem/article/view/23719.