(1999). World population hits 6 billion today. Philippine Daily Inquirer.
Lua i Stíl Chicago (17ú heag.)"World Population Hits 6 Billion Today." Philippine Daily Inquirer 1999.
Lua MLA (9ú heag.)"World Population Hits 6 Billion Today." Philippine Daily Inquirer, 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.