Davis, Michael, "Socrates' Pre-Socratism: Some Remarks on the Structure of Plato's Phaedo," Review of Metaphysics, Vol. 33, No. 3 (March 1980).

Excerpt:

To Speak of Socrates’ pre-Socraticism is puzzling. It suggests that there was a time at which Socrates was not Socrates. That is not entirely misleading. There was something special about Socrates, special enough so that Nietzsche, for one, thought it appropriate to name a problem after him.

Online:
Philosophy Documentation Center