MLA

Hagedorn, Hermann, 1882-1964. You are the hope of the world! An appeal to the girls and boys of America, by Hermann Hagedorn.. 1917. https://collections.library.yale.edu/catalog/16173389.

APA, 6th edition

Hagedorn, Hermann, 1882-1964. (1917)[You are the hope of the world! An appeal to the girls and boys of America, by Hermann Hagedorn.]. https://collections.library.yale.edu/catalog/16173389.