References in other works. Suetonius, for example:
At last he even wrote historical works in Greek, twenty books of Etruscan History and eight of Carthaginian. Because of these works there was added to the old Museum at Alexandria a new one called after his name, and it was provided that in the one his Etruscan History should be read each year from beginning to end, and in the other his Carthaginian, by various readers in turn, in the manner of public recitations.
I’m sure there’s an obvious answer, but how do we know all about what he wrote but not have any of it?
References in other works. Suetonius, for example: