Gaya APA
Tietz, R., Tietz, E. (1984).
Complete book of effective personal letters .
Englewood Cliffs, NJ:
Prentice Hall.
Gaya MLA
Tietz, Robert., Tietz, Elaine.
"Complete book of effective personal letters".
Englewood Cliffs, NJ:
Prentice Hall,
1984.
Text.