I have a list which contains XML strings. How can I sort this list according to one of the XML attribute?

For example:

The list is defined as: List listOfXML = new List();

If this list contains 3 XML strings as given below, how can I sort this list according to "ThirdAttribute"?

XML string 1:

<Element>  
  <FirstAttribute>A</FirstAttribute>> 
  <SecondAttribute>B</SecondAttribute> 
  <ThirdAttribute>3</ThirdAttribute> 
</Element>

XML string 2:

<Element>  
   <FirstAttribute>C</FirstAttribute>> 
   <SecondAttribute>D</SecondAttribute> 
   <ThirdAttribute>4</ThirdAttribute> 
</Element>

XML string 3:

<Element>  
   <FirstAttribute>A</FirstAttribute>> 
   <SecondAttribute>B</SecondAttribute> 
   <ThirdAttribute>1</ThirdAttribute> 
</Element>