Gaya APA
Whitehead, G., Whitehead, D, H. (1989).
Pitman business correspondence .
Jakarta:
Penerbit Binarupa Aksara.
Gaya MLA
Whitehead, Geoffrey., Whitehead, David, H..
"Pitman business correspondence".
Jakarta:
Penerbit Binarupa Aksara,
1989.
Teks.