- AudiolibroHow I Raised Myself from Failure to Success in SellingFrank Bettger
- AudiolibroHow I Raised Myself From Failure to Success in SellingFrank Bettger
- AudiolibroHow One Idea Increased My Income and HappinessFrank Bettger
- AudiolibroComo Triunfe en las VentasFrank Bettger
- AudiolibroHow One Idea Multiplied My Income and HappinessFrank Bettger