Verma,Ravindra. (2010). Tourism in 21st century. Centrum Press.
Chicago Style aipamenaVerma,Ravindra. Tourism in 21st Century. New Delhi: Centrum Press, 2010.
MLA aipamenaVerma,Ravindra. Tourism in 21st Century. Centrum Press, 2010.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.