1. C. S. Smith:Met Trans. A, 1975, vol. 6A, p. 603.
2. M. Tenenbaum:Met. Trans. A, 1976, vol. 7A, p. 339.
3. W. O. Baker:Met. Trans. A, 1976, vol. 8A, p. 339.
4. For an excellent historical description of the evolution of the Periodic Table see: J. W. van Spronsen:The Periodic System of Chemical Elements: A History of the First Hundred Years, Elsevier Publishing Co., Amsterdam, London, New York, 1969.
5. Das naturliche System der chemischen Elemente, Abhandlungen von Lothar Meyer and D. Mendelejeff, K. Seubert, ed., Ostvvald’s Klassiker No. 68, Leipzig, 1895.