Alcala, A. (2008). Agusan River estuary development potential. Malaya.
Chicago Style aipamenaAlcala, Angel. "Agusan River Estuary Development Potential." Malaya 2008.
MLA aipamenaAlcala, Angel. "Agusan River Estuary Development Potential." Malaya, 2008.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.