Leading development areas provinces according to level of socio-economic development.
| বিন্যাস: | মানচিত্র | 
|---|---|
| ভাষা: | English | 
| প্রকাশিত: | Manila
          Department of Public Works and Communications
    
        1971. | 
| মালা: | Physical planning strategy for the Philippines series
              16 |