Gaya APA
al., E. et al (1983).
Practical Guide To Bussiness Correspondence (pedoman Praktis Korespondensi Enggeris .
Jakarta:
Simplex.
Gaya MLA
al., Et. et al.
"Practical Guide To Bussiness Correspondence (pedoman Praktis Korespondensi Enggeris".
Jakarta:
Simplex,
1983.
Text.