Ingold, C. K.; Ingold, E. H. (1926). «The Nature of the Alternating Effect in Carbon Chains. Part V. A Discussion of Aromatic Substitution with Special Reference to Respective Roles of Polar and Nonpolar Dissociation; and a Further Study of the Relative Directive Efficiencies of Oxygen and Nitrogen». J. Chem. Soc.: 1310–1328. doi:10.1039/jr9262901310.
