Guizzo, E. How to Keep 18 Million People Moving. IEEE spectrum.
Cita Chicago (17th ed.)Guizzo, E. "How to Keep 18 Million People Moving." IEEE Spectrum .
Cita MLA (9th ed.)Guizzo, E. "How to Keep 18 Million People Moving." IEEE Spectrum, .
Atenció: Aquestes cites poden no estar 100% correctes.