Cita APA (7th ed.)

Matthies, K., & Timm, H. (1998). World commodity prices 1998 - 1999.

Cita Chicago (17th ed.)

Matthies, Klaus, i Hans-Joachim Timm. World Commodity Prices 1998 - 1999. Hamburg, 1998.

Cita MLA (8th ed.)

Matthies, Klaus, i Hans-Joachim Timm. World Commodity Prices 1998 - 1999. 1998.