Bernal, J. D. (1969). Science in history. Penguin.
Cita Chicago (17th ed.)Bernal, John Desmond. Science in History. Harmondsworth: Penguin, 1969.
Cita MLA (9th ed.)Bernal, John Desmond. Science in History. Penguin, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.