Nawazish A. Khan and S.M. Hasnain, Excess conductivity of Cu_0.5Tl_0.5Ba₂Ca₃Cu_4–yZn_yO_12–δ, Low Temp. Phys. 38, (2011) [Fiz. Nizk. Temp. 38, 28-38, (2011)] DOI: https://doi.org/10.1063/1.3677234.