Gaya APA
Soil conservation: probl ems and prospects. (1981).
New York:
John Wiley & Sons.
Gaya Chicago
Soil conservation: probl ems and prospects.
.
New York:
John Wiley & Sons,
1981.
Tesis.
Gaya MLA
Soil conservation: probl ems and prospects.
.
New York:
John Wiley & Sons,
1981.
Tesis.
Gaya Turabian
Soil conservation: probl ems and prospects.
New York:
John Wiley & Sons,
1981.
Tesis.