1. Hammett LP (1940) Physical organic chemistry. McGraw-Hill, New York, London
2. Jaffe HH (1953) Chem Rev 53:191
3. Exner O (1972) In: Chapman NB, Shorter J (eds) Advances in linear free energy relationships. Plenum Press, London
4. Krygowski TM, Stępień BT (2005) Chem Rev 105:3482
5. Smith MB, March J (2001) March’s advanced organic chemistry: reactions, mechanisms and structure, 5th edn. John Wiley & Sons, New York, pp 681–685