F. Fawwaz, B. Sweileh, R. Massad, and E. Aljamal, “Removal of Pb(II), Zn(II), Sn(II) and Cu(II) Ions from Aqueous Solutions by Linear Alternating Poly(4,4’-biphenol oxalate) Oligomer”, jjc, vol. 15, no. 2, pp. 73-85, Feb. 2021.