There is a proposal by Kontsevich how these branes should be described. He didn't write it up, but it has been reviewed in the paper math.AG/0302304, by D.Orlov. Some relations to physics are scattered around, there is a series of papers by Kapustin and Li, I have written a paper with Herbst, Lerche, Scheuner. The latest physics papers are the two recent papers Diaconescu etal hep-th/0401135, which is I think very interesting, and Hori, hep-th/0401139.