APA (7th ed.) Citation

CHUA. (1991). DOS 4: A step-by-step guide. Federal Publications.

Chicago Style (17th ed.) Citation

CHUA. DOS 4: A Step-by-step Guide. Shah Alam, Selangor: Federal Publications, 1991.

MLA (8th ed.) Citation

CHUA. DOS 4: A Step-by-step Guide. Federal Publications, 1991.

Warning: These citations may not always be 100% accurate.