In fact, we faced a real challenge with Simon's beginning tendency to snap (nasty sound) at both Alvin and us. So, I contacted the breeder as well as talking to the vet. Both suggested a form of the alpha roll (turning the pup on his side or back to assert dominance) when the pup snaps at one of us. According to the vet, the form of aggression is not usually seen in a dog so young.
The breeder also suggested the following book:
Once I get my hands on it, I plan on using it for both puppies. The Amazon reviews are very positive and it comes highly recommended by both trainers and breeders. The one negative reviewer has an issue with the alpha roll. Everyone has an opinion!