Prasad, P. G. (2012). Ecotourism and its development. Altar.
Chicago Style aipamenaPrasad, P.N. Girija. Ecotourism and Its Development. New Delhi: Altar, 2012.
MLA aipamenaPrasad, P.N. Girija. Ecotourism and Its Development. Altar, 2012.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.