1. Engelhardt, W. v.: Z. Kristallogr.106, 430?459 (1955).
2. Klug, H. P., andL. E. Alexander: X-ray diffraction procedures. New York 1954.
3. Leroux, J., D. H. Lennox andK. Kay: Analyt. Chem.25, 740?743 (1953).
4. Winkler, H. G. F.: Geochim. et Cosmochim. Acta1957.