Lewis, P. (1977). MAPS AND STATISTICS. Metbuen & Co Ltd.
Cita Chicago (17th ed.)Lewis, Peter. MAPS AND STATISTICS. UK: Metbuen & Co Ltd, 1977.
Cita MLA (9th ed.)Lewis, Peter. MAPS AND STATISTICS. Metbuen & Co Ltd, 1977.
Atenció: Aquestes cites poden no estar 100% correctes.