Helfand, L., & Naresh Kumar. (2014). They changed the world: Edison-Tesla-Bell. Kalyani Navyug Media Pvt Ltd.
Cita Chicago Style (17a ed.)Helfand, Lewis, y Naresh Kumar. They Changed the World: Edison-Tesla-Bell. New Delhi, India: Kalyani Navyug Media Pvt Ltd, 2014.
Cita MLA (8a ed.)Helfand, Lewis, y Naresh Kumar. They Changed the World: Edison-Tesla-Bell. Kalyani Navyug Media Pvt Ltd, 2014.
Precaución: Estas citas no son 100% exactas.