V. A. KOSTYLEV, N. M. CHEBOTAEV, S. V. NAUMOV, and A. A. SAMOKHVALOV, Dependence of YBa₂Cu₃O_x single crystals kinetic properties on oxygen content, Low Temp. Phys. 17, (1991) [Fiz. Nizk. Temp. 17, 10621-1065, (1991)].