Cita APA (7th ed.)

Purves,. (1977). Trace Element contamination of the environ. Elsevier.

Cita Chicago (17th ed.)

Purves. Trace Element Contamination of the Environ. Amsterdam: Elsevier, 1977.

Cita MLA (9th ed.)

Purves. Trace Element Contamination of the Environ. Elsevier, 1977.