Multiple urls of same node
There are a couple of easy to use modules that will help you manage your URL aliases.  They include, 


Pathauto
Redirect
Global Redirect


The first two aliases you have sounds like the 'default' ones.  You may have created (or one of the modules you have installed automatically) created the other aliases.

All the same, you can manage your aliases (and re-directs) using the modules I mentioned.