1. S. G. Titova and J. T. S. Irvine, in Perspectives of Superconducting Temperature Increase in HTSC Copper Oxides, Ed. by J. R. Tobin (Nova Science, New York, 2008), p. 93.
2. S. G. Titova, V. A. Fotiev, A. V. Pashchenko, A. M. Burkhanov, V. V. Gudkov, I. V. Zhevstovskikh, A. V. Tkach, and V. V. Ustinov, Sverkhprovodimost: Fiz., Khim., Tekh. 4, 1010 (1991).
3. Sun Linhai, Wang Yening, Shen Huimin, and Cheng Xiaohua, Phys. Rev. B: Condens. Matter 36, 5114 (1988).
4. Wu Ting and K. Fossheim, Supercond. Sci. Technol. 6, 827 (1993).
5. A. M. Balagurov, P. Fisher, T. Yu. Kaganovich, E. Kaldis, J. Karpinski, V. G. Simkin, and V. A. Trounov, Soobshch. Ob’edin. Inst. Yad. Issled., Dubna E14-94-415 (1994).