Helfferich, F. (1962). Ion exchange. McGraw-Hill.
Cita Chicago (17th ed.)Helfferich, Friedrich. Ion Exchange. New York: McGraw-Hill, 1962.
Cita MLA (9th ed.)Helfferich, Friedrich. Ion Exchange. McGraw-Hill, 1962.
Atenció: Aquestes cites poden no estar 100% correctes.