1. Tantalum–Niobium International Study Center, T.I.C. Nibium, primary production [R]. Bulletin No. 132. 2007.
2. Extractive metallurgy of niobium [M];GUPTA,1994
3. Metallurgy of the rarer metals—6, tantalum and niobium [M];MILLER,1959
4. Transport of niobium (V) through a TBP–Alamine 336 supported liquid membrane from chloride solutions [J];CAMPDERROS;Hydrometallurgy,2001
5. International Atomic Energy Agency. Extent of environmental contamination by naturally occurring radioactive material (Norm) and technological options for mitigation. Appendix IV [R]. IAEA, 2003: 164.