1. Upor, E., Mokhai, M., and Novak, D., Photometric Methods in Inorganic Trace Analysis, Budapest: Miiszaki, 1985.
2. Ivanov, V.M., Geterotsiklicheskie azotsoderzhashchie azosoedineniya (Heterocyclic Nitrogen-containing Azo Compounds), Moscow: Nauka, 1982.
3. Zolotov, Yu.A., Tsizin, G.I., Dmitrienko, S.G., and Morosanova, E.I., Sorbtsionnoe kontsentrirovanie mikrokomponentov iz rastvorov. Primenenie v neorganicheskom analize (Adsorption Preconcentration of Trace Components from Solutions: Application in Inorganic Analysis), Moscow: Nauka, 2007.
4. Berndt, K., Harms, U., and Sonneborn, M., Anal. Chem., 1985, vol. 322, no. 2, p. 329.
5. Busev, A.I., Analiticheskaya khimiya vismuta (Analytical Chemisty of Bismuth), Moscow: Akad. Nauk SSSR, 1953.