W.-K. Dong, K.-Q. Li, Y. Zhang, L. Xu, L. Wang, and X.-Y. Dong, “Synthesis and Supramolecular Structure of 5,5’-Dihydroxy-2,2’-[1,1’-(propane-1,3-diyldioxydinitrilo)dimethylidyne]diphenol”, ajc, vol. 25, no. 8, pp. 4398–4400, Mar. 2013.