Khalid Hamdi Razzeg, et al. “Effect of Repeated Annealing on the Synthetic and Electrical Properties of Bi2-(x+y)PbxAgy Sr2Ca2Cu3O10+δ Electrically Superconductor”. Tikrit Journal of Pure Science, vol. 24, no. 4, Aug. 2019, pp. 57-61, doi:10.25130/tjps.v24i4.400.