APA

Welles S., . (1951). Seven decisions that shaped history. Estados Unidos: Harper & Row publishers.

Chicago

Welles Summer, . 1951. Seven decisions that shaped history. Estados Unidos: Harper & Row publishers.

Harvard

Welles S., . (1951). Seven decisions that shaped history. Estados Unidos: Harper & Row publishers.

MLA

Welles Summer, . Seven decisions that shaped history. Estados Unidos: Harper & Row publishers. 1951.