APA (7th ed.) Citation

Keefer, R. F., & Sajwan, K. S. (1993). Trace elements in coal and coal combustion residues. Lewis Publishers.

Chicago Style (17th ed.) Citation

Keefer, Robert F., and Kenneth S. Sajwan. Trace Elements in Coal and Coal Combustion Residues. Boca Raton: Lewis Publishers, 1993.

MLA (9th ed.) Citation

Keefer, Robert F., and Kenneth S. Sajwan. Trace Elements in Coal and Coal Combustion Residues. Lewis Publishers, 1993.