BiblioVault may have an electronic file which would meet your requirements for this title:
The Complete Tragedies, Volume 2: Oedipus, Hercules Mad, Hercules on Oeta, Thyestes, Agamemnon
Lucius Annaeus Seneca, Shadi Bartsch, Susanna Braund and David Konstan
Paper: 978-0-226-82108-5
Cloth: 978-0-226-01360-2
Electronic: 978-0-226-01374-9