1. C. K. Maclane, S. Peterson, The Transuranic Elements by Seaborg, Katz & Manning, McGraw-Hill Co., Inc., New York, 1949, p. 1388.
2. M. Haissinsky,Compt. Rend. 196 (1933) 1778–79.
3. S. Peterson, The same as 1., p. 1391.
4. Gmelins Handbuch der anorganischen Chemie, 8th ed., Actinium and Isotopes (MsTh2) System 40, pp. 46–52; 78–81. Verlag Chemie, GmbH., Berlin, 1942.
5. T. Kiba, S. Chashi, T. Maeda,Bull. Chem. Soc. Japan 33 (1960) 818.