A bark collar! Yes, perfect tool for bark training. Or a spray collar. Whenever the dog barks, a bitter apple spray will spray right in the dog's face.
instead of a bitter apple spray, you could also get a squirt gun and spray water in his face.
I generally oppose yelling as a means to discipline puppies. Remember that dogs crave human attention; even negative attention, such as yelling, is better than no attention. To discourage bad behavior, simply ignore them when they are misbehaving. I actually put my dogs in "time out" for bad behavior. Just the words "time out" now usually correct even very bad behavior for me. If you isolate them when they engage in behavior you do not like on a consistent basis, and allow them positive human interaction when they are well behaved, the problem should work itself out.
Yelling translates to barking humans for the dog. Try using appropriate dog language. A low growly voice means bad, a high squeeky voice means good, a firm middle tone is for commands. Dogs respond to facial expressions as well. A smile means "good" just like English Barred teeth means "bad". A steady stare is a warning.