Analysis of information sources in references of the Wikipedia article "Theaetetus (mathematician)" in English language version.
Thesleff, Holger (1989). "Platonic Chronology". Phronesis. 34 (1): 1–26. doi:10.1163/156852889X00017. p. 18, footnote 67: I find it essential to note that the historians of mathematics who take for granted that Theaitetos was still active in the 370s must be wrong. He made some important discoveries as a young man, and Plato and his friends were deeply impressed by this. But he is likely to have died in 390 B.C., and not likely to have written anything. When Plato wrote his first draft of the dialogue, presumably in the 370s, he saw this friend of his youth from an idealizing perspective, somewhat in the way he remembered his uncle Charmides.
