UNDP World Bank Water and Sanitation Program. Work Program Volume 1: Country Work Plan 1991-92.
Chicago Style aipamenaUNDP World Bank Water and Sanitation Program. Work Program Volume 1: Country Work Plan 1991-92.
MLA aipamenaUNDP World Bank Water and Sanitation Program. Work Program Volume 1: Country Work Plan 1991-92.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.