1. Tulyupa, F.M. and Barkalov, V.S., Zh. Obshch. Khim., 1967, vol. 37, p. 509.
2. Busev, A.I. et al., Zh. Anal. Khim., 1972, vol. 27, no. 9, p. 1802.
3. US Patent 4 764 281, 1988.
4. US Patent 4 902 665, 1988.
5. Stasinakis, A.S., Global NEST J., 2008, vol. 10, no. 3, pp. 376–385.