Orbeta, J., Orbeta, J. C. A., & Franco, B. V. J. (2001). Sec. Richard Gordon: 'Tourism is a sacred duty'. Kabayan.
Chicago Style aipamenaOrbeta, Joseph, Joseph Christian A. Orbeta, and Bernardo V. Jr Franco. "Sec. Richard Gordon: 'Tourism Is a Sacred Duty'." Kabayan 2001.
MLA aipamenaOrbeta, Joseph, et al. "Sec. Richard Gordon: 'Tourism Is a Sacred Duty'." Kabayan, 2001.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.