J.-H. Bi, F.-X. Xie, X.-D. Zhao, L.-Q. Chen, J.-D. Xu, and S.-S. Ni, “Synthesis of a New Aza-crown Ether Containing Pendant Carboxylate Groups, Its Th4+ and UO22+ Complexes and Thermodynamic Properties in Aqueous Solution”, ajc, vol. 16, no. 1, pp. 137–142, Jul. 2012.