Rosenau, B., Krieger, C., & Staab, H. A. (1985). Sterically crowded tetracyano-para-quinodimethanes: synthesis and structure of 2,3,5,6-tetramethyl-7,7,8,8-tetracyano- -quino=dimethane. Tetrahedron Letters, 26(17), 2081-2084.