(1998). BIR Tax calendar: BIR enters the age of information technology. Bureau of Internal Revenue.
Chicago Style aipamenaBIR Tax Calendar: BIR Enters the Age of Information Technology. s.l: Bureau of Internal Revenue, 1998.
MLA aipamenaBIR Tax Calendar: BIR Enters the Age of Information Technology. Bureau of Internal Revenue, 1998.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.