1. http://en.wikipedia.org/w/index.php?title=Document_Object_Model&action=history
2. http://en.wikipedia.org/w/index.php?title=Suffix_tree&oldid=649776788
3. http://www.geeksforgeeks.org/
4. en.wikibooks.org/wiki/Data_mining_Algorithms_In_R/Frequent_Pattern_Mining/The%20FP_Growth_Algorithm
5. hareenlaks.blogspot.com/2011/06/