1. Prasada, R.T., Teddy, M.L.P., and Pillai, A.R., Talanta, 1998, vol. 46, p. 765.
2. Połedniok, J. and Buhl, F., Laboratory, 2008, vol. 9, p. 22.
3. Verma, C.K., Kulshrestha, S., and Prakash, O., Chem. Anal. (Warsaw), 1983, vol. 28, p. 669.
4. Marczenko, Z. and Jarosz, M., Analyst, 1984, vol. 109, p. 35.
5. Kwapulin-ska, G., Proc. University of Silesia, 1990, vol. 1119, p. 43.