Howarth, S. (1992). Sea Shell: The story of Shell's British tanker fleets, 1892-1992. Thomas Reed.
Cita Chicago Style (17a ed.)Howarth, Stephen. Sea Shell: The Story of Shell's British Tanker Fleets, 1892-1992. London [etc.]: Thomas Reed, 1992.
Cita MLA (9a ed.)Howarth, Stephen. Sea Shell: The Story of Shell's British Tanker Fleets, 1892-1992. Thomas Reed, 1992.
Precaución: Estas citas no son 100% exactas.