If you haven't tried formal dog training that would be one of my first steps.
Your local petsmart has inexpensive classes.
One of the dogs in our puppy class was somewhat aggressive,(even bit the trainer and another pet owner in our class) and after trying numerous things a simple spray bottle with water was all it took.
When their dog started being aggressive they would say "stop" or "No" and spray him with a short mist of water. It worked for them...you could try it.
The training would also help with the paper shredding....
Michele & Bailey
