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.
芝加哥风格引文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.
MLA引文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.
警告：这些引文格式不一定是100％准确.