Orig, T. S. (1999). Photovoltaic (PV) technology can stop people from migrating to congested cities. Manila Bulletin.
Chicago-referens (17:e uppl.)Orig, Thor S. "Photovoltaic (PV) Technology Can Stop People from Migrating to Congested Cities." Manila Bulletin 1999.
MLA-referens (9:e uppl.)Orig, Thor S. "Photovoltaic (PV) Technology Can Stop People from Migrating to Congested Cities." Manila Bulletin, 1999.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.