Citation: J. Macicek et al., STRUCTURES OF 1,1-DIPHENYL-2-AZA-1,3-BUTADIENES .4. 4-DICHLOROPHENYL)-1,1-DIPHENYL-2-AZA-1,3-BUTADIENE (24CLPD) AND -DIMETHOXYPHENYL)-1,1-DIPHENYL-2-AZA-1,3-BUTADIENE (24MOPD), Acta crystallographica. Section C, Crystal structure communications, 49, 1993, pp. 2169-2173