Antonio, T. (1997). Duty-free shops illegal? Manila Bulletin.
Chicago Style aipamenaAntonio, Tony. "Duty-free Shops Illegal?" Manila Bulletin 1997.
MLA aipamenaAntonio, Tony. "Duty-free Shops Illegal?" Manila Bulletin, 1997.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.