I'm going to be writing a paper on Ptolemaic Egypt for one of my classes this semester, and one of the requirements for the paper is that we must use only primary or secondary sources. So aside from the plethora of secondary sources such as Polybius and Arrian, what primary sources are there?

So far I have thought only of coinage, papyri, and inscriptions.

As the paper will most likely deal with how the Ptolemaic government interacted with the native Egyptians, it seems as though a good source will be the various papyri which the natives used. Does anyone know where I can find a book of those papyri?