Larned, J. N., & Reiley, A. C. (1901). History for ready reference: From the best historians, biographers, and specialists; their own words in a complete system of history. Springfield, Mass: The C.A. Nichols Co.. p. 440. [cf., At about the same time [1888], Galileo Ferraris, in Italy, and Nikola Tesla, in the United States, brought out motors operating by systems of alternating currents displaced from one another in phase by definite amounts and producing what is known as the rotating magnetic field.]