Gaya APA

R., R, S. (1997). Tour and Travel Economy (Ekonomi Pariwisata) . [s.l.]: SMIP Untag '45.

Gaya MLA

R., Richard, Sihite. "Tour and Travel Economy (Ekonomi Pariwisata)". [s.l.]: SMIP Untag '45, 1997. Text.