Das Lichtmikroskop öffnete das erste Tor zum Mikrokosmos. Das Elektronenmikroskop öffnete das zweite Tor zum Mikrokosmos. Was werden wir finden wenn wir das dritte Tor öffnen?
as quoted by Nan Yao, director of the Imaging and Analysis Center at the Princeton Materials Institute, in the Princeton Weekly Bulletin, February 26, 2001, Vol. 90, No. 18 http://www.princeton.edu/~iac/pwb2_26b.html.
Ernst Ruska: Frases em inglês
On the advantage of facing doubt when one has discovered something new. Speech at the Nobel Banquet, December 10, 1986 http://nobelprize.org/nobel_prizes/physics/laureates/1986/ruska-speech.html.