Using quotes correctly

This is the introduction to my country report:

     America is one of  largest multiculture nations in the world. American is the world’s third or forth largest country located in North America with about 300 million populations [1].  There are 48 contiguous states in America and the capital is Washington DC [1]. America is the financial center of the world and its economy is the world's largest national economy with over nighteen percent of global GDP. [1][2] Its per capita income is the seventh highest in the world with about 48,100 USD in 2011[1]. What's more,  America has the top quality of education and the highest reputation of its Universities. According to prominent international rankings, 13 or 15 American colleges and universities are ranked among the top 20 in the world like Harvard University, Stanford university and Columbia University [3].

[1]  https://www.cia.gov/library/publications/the-world-factbook/geos/us.html

[2]  http://www.imf.org/external/pubs/ft/weo/2011/02/weodata/weorept.aspx?sy=2009&ey=2016&scsm=1&ssd=1&sort=country&ds=.&br=1&c=111&s=NGDPD%2CNGDPDPC%2CPPPGDP%2CPPPPC%2CLP&grp=0&a=&pr1.x=49&pr1.y=17
[3]  http://www.topuniversities.com/university-rankings/world-university-rankings/2010