APA

Lepp I., . (1971). The challenges of life. New York: Image Books.

Chicago

Lepp Ignace, . 1971. The challenges of life. New York: Image Books.

Harvard

Lepp I., . (1971). The challenges of life. New York: Image Books.

MLA

Lepp Ignace, . The challenges of life. New York: Image Books. 1971.