[1] Zhang, H. The Birth of the Weather Forecast and History of the Weather Forecast.
http://www.weather.com.cn
[2] (2010) Weather Forecast Values. Xi’an and Lanzhou Historical Weather Forecast.
http://www.weather121.com
[3] Xi’an 2012 6/7/8 Month Weather Charts. Xi’an Historical Weather, Historical Weather Inquiry. http://www.tianqi.com
[4] The Hottest Place on Earth. Highest in the World.
http://www.findwz.com
[5] Antarctic Vostok/The World’s Coldest Five Places.
http://www.360doc.com/
[6] Enter Dates. Historical Data.
http://www.wunderground.com