APA Style
PENN, W.S. (1960).
Soil classification : a comprehensive system, 7th Appoximation .
Washington:
USDA.
Chicago Style
PENN, W.S.
Soil classification : a comprehensive system, 7th Appoximation.
Washington:
USDA,
1960.
Hard Copy.
MLA Style
PENN, W.S.
Soil classification : a comprehensive system, 7th Appoximation.
Washington:
USDA,
1960.
Hard Copy.
Turabian Style
PENN, W.S.
Soil classification : a comprehensive system, 7th Appoximation.
Washington:
USDA,
1960.
Hard Copy.