Estos valores son los valores originales obtenidos por Hammett en su publicación de 1937, y pueden diferir de publicaciones posteriores enviadas por otras personas. El siguiente enlace contiene constante de sustituyentes comúnmente aceptados: C. Hansch, A. Leo and R. W. Taft (1991). «A survey of Hammett substituent constants and resonance and field parameters». Chem. Rev.91 (2): 165-195. doi:10.1021/cr00002a004.
Keenan, Sheue L.; Peterson, Karl P.; Peterson, Kelly; Jacobson, Kyle (2008). «Determination of Hammett Equation Rho Constant for the Hydrolysis of p-Nitrophenyl Benzoate Esters». J. Chem. Educ.85 (4): 558. Bibcode:2008JChEd..85..558K. doi:10.1021/ed085p558.
Hammett, Louis P. (1937). «The Effect of Structure upon the Reactions of Organic Compounds. Benzene Derivatives». J. Am. Chem. Soc.59 (1): 96. doi:10.1021/ja01280a022.
Louis P. Hammett (1935). «Some Relations between Reaction Rates and Equilibrium Constants». Chem. Rev.17 (1): 125-136. doi:10.1021/cr60056a010.
Swain, C. Gardner; Lupton, Elmer C. (1968). «Field and resonance components of substituent effects». publicación of the American Chemical Society90 (16): 4328-4337. doi:10.1021/ja01018a024.
Hansch, Corwin; Leo, A.; Taft, R. W. (1991). «A survey of Hammett substituent constants and resonance and field parameters». Chemical Reviews91 (2): 165-195. doi:10.1021/cr00002a004..
Catalán, Javier; Díaz, Cristina; García-Blanco, Francisco (1999). «Correlation of Solvolysis Rates 50 años Later». The publicación of Organic Chemistry64 (17): 6512-6514. doi:10.1021/jo990588w.
Bols, Mikael; Liang, Xifu; Jensen, Henrik H. (2002). «Equatorial contra axial polar substituents. The relation of a chemical reaction to stereochemical substituent constants». J. Org. Chem.67 (25): 8970. doi:10.1021/jo0205356.
Westheimer F.H. (1939). «The Electrostatic effect of substituents on the dissociation constants of organic acids. IV. Aromatic acids». J. Am. Chem. Soc.61 (8): 1977. doi:10.1021/ja01877a012.
Roberts J.D.; Moreland Jr. W.T. (1953). «Electrical Effects of Substituent Groups in Saturated Systems. Reactivities of 4-Substituted Bicyclo [2.2.2] octane-1-carboxylic acids». J. Am. Chem. Soc.75 (9): 2167-2173. doi:10.1021/ja01105a045.
Um, Ik-Hwan; Lee, Ji-Youn; Kim, Han-Tae; Bae, Sun-Kun (2004). «Curved Hammett plot in alkaline hydrolysis of O-aryl thionobenzoates: Change in rate-determining step versus ground-state stabilization». J. Org. Chem.69 (7): 2436-2441. doi:10.1021/jo035854r.
Young, P. R.; Jencks, W. P. (1979). «Separation of polar and resonance substituent effects in the reactions of acetophenones with bisulfite and of benzyl halides with nucleophiles». J. Am. Chem. Soc.101 (12): 3288. doi:10.1021/ja00506a025.
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Keenan, Sheue L.; Peterson, Karl P.; Peterson, Kelly; Jacobson, Kyle (2008). «Determination of Hammett Equation Rho Constant for the Hydrolysis of p-Nitrophenyl Benzoate Esters». J. Chem. Educ.85 (4): 558. Bibcode:2008JChEd..85..558K. doi:10.1021/ed085p558.
Y. Yukawa & Y. Tsuno, 1959, "Resonance Effect in Hammett Relationship. II. Sigma Constants in Electrophilic Reactions and their Intercorrelation," Bull. Chem. Soc. Jpn.32:965-971, see [1], accessed 22 June 2015.