1. Technology of Scandium Ytterbium and the Rare Earth Metals;Lowe,1963
2. Rare Earth Research;Deane,1961
3. Chimia i technologia redkich i rassejanych elementov;Bolšakov,1976
4. Solvent Extraction;Ritcey,1979
5. Spravočnik po cvetnym i redkim metallam i ich soiedinjenijam primenjaemym v laboratornoj praktite;Porozenko,1962