Anyone BUT Greenbelt Dog Training. They use old fashioned methods based on fear and intimidation. Look up a Positive Dog trainer such as Rewards Dog Training, by Joyce Loebig http://www.rewardsdogtraining.com/index.html If you are willing to go to Columbia, The Coventry School there is excellent also. http://thecoventryschool.com/ Both owners continue their education and use behaviorally sound methods based in positive reinforcement.