Gaya APA
ASTM, . (1997).
ASTM D 2487 - 93 ; ASTM D 2487 - 00 Standard classification of soils for engineering purposes (United soil classification system) .
:
ASTM.
Gaya MLA
ASTM, .
"ASTM D 2487 - 93 ; ASTM D 2487 - 00 Standard classification of soils for engineering purposes (United soil classification system)".
:
ASTM,
1997.
Diorama.