C4.5 is one of the most well known variants of Quinlan's ID3 decision tree learning algorithm. C4.5 has a number of variations from basic ID3 including the use of normalised information gain for non-binary node decisions.
Used in glossary entries: decision tree, ID3, information gain ratio, Quinlan, Ross
Links:
Wikipedia: C4.5 algorithm- YouTube: C4.5 Decision Tree algorithm