Gaya APA

Directive English Sound. ([s.n]). : Karya Utama.

Gaya Chicago

Directive English Sound. . : Karya Utama, [s.n]. .

Gaya MLA

Directive English Sound. . : Karya Utama, [s.n]. .

Gaya Turabian

Directive English Sound. : Karya Utama, [s.n]. .