Wang, Li, et al. “Synthesis and Crystal Structure of 3,3’-Dimethyloxy-1,1’-[butane-1,4-diyldioxybis(nitrilomethylidyne)]dibenzene”. Asian Journal of Chemistry, vol. 25, no. 7, Feb. 2013, pp. 4115-6, doi:10.14233/ajchem.2013.13969.