APA-referens (7:e uppl.)

(1989). Study on regional travel in the Philippines 1989. DOT/AIT.

Chicago-referens (17:e uppl.)

Study on Regional Travel in the Philippines 1989. [Quezon City]: DOT/AIT, 1989.

MLA-referens (9:e uppl.)

Study on Regional Travel in the Philippines 1989. DOT/AIT, 1989.