1. Whitler, J. and Roth, R.S., Phase Diagrams for High Tc Superconductors, Westerville: Amer. Ceram Soc., 1991.
2. Karen, P., Braaten, O., and Kjekshus, A., Acta Chem. Scand., 1992, p. 805.
3. Osamura, K. and Zhang, W., Z. Metallkd., 1993, vol. 84, p. 522.
4. Diagrammy sostoyaniya sistem tugoplavkikh oksidov: Spravochnik. Vyp. 6. Sistemy keramicheskikh vysokotemperaturnykh sverkhprovodnikov (Phase Diagrams of Systems of Refractory Oxides: Handbook. Issue 6: Systems of Ceramic High-Temperature Superconductors), St. Petersburg: Nauka, 1997.
5. Karen, P. and Kjekshus, A., Handbook of the Physics and Chemistry of Rare Earth, Elsevier Sci., 2000, vol. 30, p. 229.