Gw mau tau Rujukan dari John Hasbrouck Van Vleck. Jelasin dalam bahasa melayu

The Theory of Electric and Magnetic Susceptibilities

Duncan, Anthony and Janssen, Michel. "On the verge of Undeutung in Minnesota: Van Vleck and the correspondence principle. Part one," Archive for History of Exact Sciences 2007, 61:6, pages 553–624.