Public domain. Cover image from Project Gutenberg ebook #68565. To the sons of tomorrow auctore Jr. Irving E. Cox Detrahe .m4b · 58 MB Quomodo audiendum → · Problema cum hac recitatione? Animadversionem mitte → Recitator Arthur — English RP Narrator (en-GB) Diuturnitas 57 min Lingua English Additum November 7, 2026 Liber electronicus originalis Project Gutenberg Licentia Public domain FictionScience Fiction