APA aipamena

Stephenson, H. (2019). Life: Wordbook. National geographic learning.

Chicago Style aipamena

Stephenson, Helen. Life: Wordbook. National geographic learning, 2019.

MLA aipamena

Stephenson, Helen. Life: Wordbook. National geographic learning, 2019.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.