BiblioVault may have an electronic file which would meet your requirements for this title:
Brother Men: The Correspondence of Edgar Rice Burroughs and Herbert T. Weston
Edgar Rice Burroughs, Herbert T. Weston and Matt Cohen
Paper: 978-0-8223-3541-2
Cloth: 978-0-8223-3529-0
Electronic: 978-0-8223-8646-9