I have John Tressler (son of Goodhart & Catharine Tressler) b. 8/1844 Henry Clay Twp., Fayette Co., PA m. Mary Elizabeth Bryner (dau. of John Henry Bryner & Moriah Jane Tissue). I have the following children: John, Calvin, William H., Sarah Ellen, Samuel, Isaac, Elisha, Charles & Lizzie.
Much of my Tressler research was passed down to me from an aunt. I've been researching for almost twenty years and have had more trouble with the Tressler branch of my tree than any other. I don't have any sources, but it might be helpful in your research.
I am the great-great-granddaughter of John's brother, Clark.