(1963). Gateway to the great books 8: Natural science. Encyclopedia Britannica.
Cita Chicago (17th ed.)Gateway to the Great Books 8: Natural Science. Chicago, Estados Unidos: Encyclopedia Britannica, 1963.
Cita MLA (9th ed.)Gateway to the Great Books 8: Natural Science. Encyclopedia Britannica, 1963.
Atenció: Aquestes cites poden no estar 100% correctes.