Mike quote:

"...Timaeus and Critias, written by Plato some time around 360 BC are the only existing ancient written records which specifically refer to Atlantis. The dialogues are conversations between Socrates, Hermocrates, Timaeus, and Critias. Apparently in response to a prior talk by Socrates about ideal societies, Timaeus and Critias agree to entertain Socrates with a tale that is “not a fiction but a true story...”

This is not certain. Exist others references before and after Plato. Look the Georgeos Diaz-Montexano's investigations.