John Boardman "Thebes (1)" The Oxford Classical Dictionary . Simon Hornblower and Anthony Spawforth. © Oxford University Press 1949, 1970, 1996, 2005.
"[9.8.4] In the circuit of the ancient wall of Thebes were gates seven in number, and these remain to-day. One got its name, I learned, from Electra, the sister of Cadmus, and another, the Proetidian, from a native of Thebes. He was Proetus, but I found it difficult to discover his date and lineage. The Neistan gate, they say, got its name for the following reason. The last of the harp's strings they call nete, and Amphion invented it, they say, at this gate. I have also heard that the son of Zethus, the brother of Amphion, was named Neis, and that after him was this gate called."
Pausanias. Description of Greece. Translated by Jones, W. H. S. and Omerod, H. A. Loeb Classical Library Volumes. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1918.
Diodorus Siculus describes the was of the Epigoni against Thebes:
Next: The Theban Stories
"[4.66.1] As for The Seven against Thebes, such, then, was the outcome of their campaign. But their sons, who were known as Epigoni, being intent upon avenging the death of their fathers, decided to make common cause in a campaign against Thebes, having received an oracle from Apollo that they should make war upon this city, and with Alcmaeon, the son of Amphiaraüs, as their supreme commander."
Diodorus Siculus. Library of History (Books III - VIII). Translated by Oldfather, C. H. Loeb Classical Library Volumes 303 and 340. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1935.