APA (7th ed.) Citation

Heinlein, R. A. (1957). The door into summer. New American Library.

Chicago Style (17th ed.) Citation

Heinlein, Robert A. The Door into Summer. New York: New American Library, 1957.

MLA (9th ed.) Citation

Heinlein, Robert A. The Door into Summer. New American Library, 1957.

Warning: These citations may not always be 100% accurate.