Frey, W. H. Three Americas: The rising significance of regions. Journal of the American Planning Association.
芝加哥风格引文Frey, William H. "Three Americas: The Rising Significance of Regions." Journal of the American Planning Association .
MLA引文Frey, William H. "Three Americas: The Rising Significance of Regions." Journal of the American Planning Association, .
警告：这些引文格式不一定是100％准确.