The evidence for Aristotle's Protrepticus 

1. Reports of Aristotle's Protrepticus

2. Oxyrhynchus Papyrus 666  

3. Oxyrhynchus Papyrus 3699

4. Oxyrhynchus Papyrus 3659

5. Vindob Papyrus G 26008

6. Iamblichus, On the common mathematical science, chapter 26

7. Iamblichus, Exhortation to Philosophy, chapters 6-12 

8. Proverbs attributed to Aristotle in the ancient wisdom literature