Whitten, Kenneth W.; Gailey, Kenneth D.; Davis, Raymond E. (1992). General Chemistry (edisi ke-4). Saunders College Publishing. hlm. 660. ISBN0-03-072373-6.
Miessler, Gary L.; Tarr, Donald A. (1991). Inorganic Chemistry (edisi ke-2). Prentice Hall. ISBN0-13-465659-8. Chapter 6: Acid–Base and Donor–Acceptor Chemistry