Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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