Allen; Bell
Journal of the American Chemical Society, 1940 , vol. 62, p. 2408,2411
Org. Synth. Coll., 1955 , vol. Vol. III, p. 310

I.G. Farbenind.
Patent: DE498360 , 1928 ;
Fortschr. Teerfarbenfabr. Verw. Industriezweige, vol. 17, p. 1138