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2. E. V. Anslyn and D. A.Dougherty , Modern Physical Organic Chemistry , University Science Books , Sausalito , 2006 , pp. 288–292 , 567–568
3. M. B. Smith , March's Advanced Organic Chemistry , Wiley , Hoboken , 7th edn, 2013 , pp. 446–450
4. Hard and Soft Acids and Bases
5. Acids and Bases