Philippines. Department of Public Works, Transportation and Communications. Planning and Project Development Office. PPDO geographical coding scheme. [s.n.
Chicago Style (17th ed.) CitationPhilippines. Department of Public Works, Transportation and Communications. Planning and Project Development Office. PPDO Geographical Coding Scheme. Manila: [s.n.
MLA (9th ed.) CitationPhilippines. Department of Public Works, Transportation and Communications. Planning and Project Development Office. PPDO Geographical Coding Scheme. [s.n.
Warning: These citations may not always be 100% accurate.