Answers by Expert:
I specialize in U.S. three-cent nickels, but also close behind them are U.S. two-cent pieces, three-cent silver, and twenty cent pieces. Also, I have a bit of experience in the area of U.S. Early Proofs (19th century). However, I can possibly assist in most questions regarding U.S. Type coins.
I have read virtually everything I can find in print on the areas of U.S. 2-3-20 cent pieces. I have written articles on three-cent coins and Early Proofs published (or will be published) in Coin World.
MS in Mathematical Physics ANA Advanced Grading and Problem Coins seminar