APA

Du Bois W. P., . (1947). The twenty-one balloons. New York: The Viking press.

Chicago

Du Bois William Pène, . 1947. The twenty-one balloons. New York: The Viking press.

Harvard

Du Bois W. P., . (1947). The twenty-one balloons. New York: The Viking press.

MLA

Du Bois William Pène, . The twenty-one balloons. New York: The Viking press. 1947.