http://www.bbc.co.uk/schools/gcsebitesize/history/tch_wjec/usa19101929/1immigration8.shtml
http://www.gcsehistory.org.uk/modernworld/usa/racismandintolerance.htm
http://www.ushistory.org/us/47c.asp
http://benluke1920.weebly.com/intolerance-and-suspicion.html