APA (7th ed.) Citation

Helfand, L., & Naresh Kumar. (2014). They changed the world: Edison-Tesla-Bell. Kalyani Navyug Media Pvt Ltd.

Chicago Style (17th ed.) Citation

Helfand, Lewis, and Naresh Kumar. They Changed the World: Edison-Tesla-Bell. New Delhi, India: Kalyani Navyug Media Pvt Ltd, 2014.

MLA (8th ed.) Citation

Helfand, Lewis, and Naresh Kumar. They Changed the World: Edison-Tesla-Bell. Kalyani Navyug Media Pvt Ltd, 2014.

Warning: These citations may not always be 100% accurate.