1. D. I. Mendeleev, Zh. Russ. Khim. Obshch., 1, No.1, 60 (1869).
2. K. Masanori, Bull. History Chem., No. 27(1), 4 (2002).
3. L. Boiabaudran, C. R. Hebd. Seanc. Acad. Sci., No. 81, 493 (1875).
4. C. Winkler, Ber. Deutsch. Chem. Gesellsch., No. 19, 210 (1886).
5. C. Winkler, J. Prakt. Chem., No. 34, 177 (1886).