G. Q. MEMON, Z. A. KALHORO, and A. W. SHAIKH, “Invariant Solution of Viscoelastic Fluid flow in Channels without Porous Media Attached with Constitutive Model of Oldroyd–B Resolved By Symmetry Method”, Sindh. Uni. Res. J. SS, vol. 49, no. 1, Jan. 2021.