To help establish the text, the older evidence of papyri and the independent evidence of the testimony of commentators and other authors (i.e., those who quote and refer to an old text of Plato which is no longer extant) are also used. Many papyri which contain fragments of Plato's texts are among the Oxyrhynchus Papyri. The 2003 Oxford Classical Texts edition by Slings even cites the Coptic translation of a fragment of the "Republic" in the Nag Hammadi library as evidence. Important authors for testimony include Olympiodorus the Younger, Plutarch, Proclus, Iamblichus, Eusebius, and Stobaeus.