Initial statement of the Uncertainty principle in "Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik" in Zeitschrift für Physik, 43 (1927)
Variant translation: The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.
As quoted in "The Uncertainty Principle" at the American Institute of Physics http://www.aip.org/history/heisenberg/p08.htm
