"Source: Freebase - The World's database". . . . . . . . "a5e3acff2a41e6555dbd5c2257a70f253aed6b668e71d9e2f3dfc112ff273465". "Tesla's US390721 Patent for a \"Dynamo Electric Machine\""@en. . "wikipedia,en,343595". . . "51757"^^. "806.0"^^. . "516.0"^^.