Howarth, S. (1997). A century in oil: The "Shell" Transport and Trading Company 1897-1997. Weidenfeld & Nicolson.
Cita Chicago (17th ed.)Howarth, Stephen. A Century in Oil: The "Shell" Transport and Trading Company 1897-1997. London: Weidenfeld & Nicolson, 1997.
Cita MLA (8th ed.)Howarth, Stephen. A Century in Oil: The "Shell" Transport and Trading Company 1897-1997. Weidenfeld & Nicolson, 1997.
Atenció: Aquestes cites poden no estar 100% correctes.