(EN) Nikola Tesla, Pioneer Radio Engineer Gives Views on Power, in New York Herald Tribune, 11 settembre 1932. URL consultato il 19 maggio 2014.
«I hold that space cannot be curved, for the simple reason that it can have no properties. It might as well be said that God has properties. He has not, but only attributes and these are of our own making. Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved, is equivalent to stating that something can act upon nothing. I, for one, refuse to subscribe to such a view.»