Gaya APA

HELLER, Robert. (2008). BILL GATES . : .

Gaya Chicago

HELLER, Robert. BILL GATES. : , 2008. Text.

Gaya MLA

HELLER, Robert. BILL GATES. : , 2008. Text.

Gaya Turabian

HELLER, Robert. BILL GATES. : , 2008. Print.