Cita APA (7th ed.)

(1975). Soil classification instruction manual / by Amster K. Howard.

Cita Chicago (17th ed.)

Soil Classification Instruction Manual / by Amster K. Howard. 1975.

Cita MLA (9th ed.)

Soil Classification Instruction Manual / by Amster K. Howard. 1975.

Atenció: Aquestes cites poden no estar 100% correctes.