United States. Bureau of the Census. Population Division. (1978). World population, 1977: Recent demographic estimates for the countries and regions of the world. U. S. Government Printing Office.
Lua i Stíl Chicago (17ú heag.)United States. Bureau of the Census. Population Division. World Population, 1977: Recent Demographic Estimates for the Countries and Regions of the World. Washington: U. S. Government Printing Office, 1978.
Lua MLA (9ú heag.)United States. Bureau of the Census. Population Division. World Population, 1977: Recent Demographic Estimates for the Countries and Regions of the World. U. S. Government Printing Office, 1978.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.