Gaya APA
Hardiyatmo, H, C., Widodo, M, P.
(1992).
Mekanika tanah 1
.
Yogyakarta:
Apress.
Gaya MLA
Hardiyatmo, Hary, Christady., Widodo, Mc, Prihminto.
"Mekanika tanah 1".
Yogyakarta:
Apress,
1992.
Text.