Original: Plato, Xenophon, and Aristotle are the main sources for the historical Socrates; however, Xenophon and Plato were direct disciples of Socrates, and presumably, they idealize him; however, they wrote the only continuous descriptions of Socrates that have come down to us. Aristotle refers frequently, but in passing, to Socrates in his writings.
Simplified: Another of Socrates' students, Xenophon also wrote about Socrates.