Gaya APA
king, F.W.. (1986).
English business letters (new edition).
Singapore:
Longman.
Gaya Chicago
king, F.W..
English business letters.
new edition
Singapore:
Longman,
1986.
CD-ROM.
Gaya MLA
king, F.W..
English business letters.
new edition
Singapore:
Longman,
1986.
CD-ROM.
Gaya Turabian
king, F.W..
English business letters.
new edition
Singapore:
Longman,
1986.
CD-ROM.