(1)
I. Ya. FUGOL, V. N. SAMOVAROV, Yu. I. RYBALKO, and V. M. ZHURAVLEV, Luminescence of charge-sensitive oxygen centers in high-temperature super conductors: the effect of superconducting transition, Low Temp. Phys. 16, (1990) [Fiz. Nizk. Temp. 16, 580-583, (1990)].