I am conducting archival research on the issues that parents have communicated about with their children in letters they mailed to their children. I am interested in things that gratified parents and things that upset them. I want to examine how these issues changed or remained the same over time. I am particularly interested in locating good archives for such letters in the NY, NJ, PA area. I have found good material at the New York Historical Society and at historical societies in Princeton and Morristown NJ. I would appreciate any information about letter archives that have already been digitized and are available online (if there are such resources). Thanks.