As a Superhuman Ethnographer, I have had the privilege of frequent contact with several Atlanteans. You may be most familiar with the Justice League member Aquaman. Most of the public refuses to use his existence as evidence for the veracity of Atlantis, but, after a few visits to the sunken city to meet with fellow ethnographer Stanly J. Kirby, I'm fairly confident it's real :D

In all seriousness, I can reccommend the documentary graphic novels The Atlantis Chronicles and Aquaman: Throne of Atlantic as quality histories of the city.