APA (7e ed.) Bronvermelding

BLUEBIRD BOOKS. (2001). CHILDREN'S REFERENCE: THE UNIVERSE. BLUEBIRD BOOKS.

Chicago (17e ed.) Bronvermelding

BLUEBIRD BOOKS. CHILDREN'S REFERENCE: THE UNIVERSE. NEW DELHI: BLUEBIRD BOOKS, 2001.

MLA (9e ed.) Bronvermelding

BLUEBIRD BOOKS. CHILDREN'S REFERENCE: THE UNIVERSE. BLUEBIRD BOOKS, 2001.