Relation of Gamma Distribution to Other Distributions

Gamma Distribution has a relation to several other distributions:
For a = 1, the Gamma Distribution reduces to the Exponential Distribution.
The well-known Chi-Square Distribution, a very widely used and famous continuous probability distribution is a particular case of Gamma Distribution i.e. for a = n/2 and ? = 1/2 the Gamma Distribution takes the form of Chi-Square Distribution with degrees of freedom as n.