Katzir, Shaul Department Structural Changes in Systems of Knowledge, Max Planck Institute for the History of Science, Max Planck Society;
Katzir, S. (2008). From ultrasonic to frequency standards: Walter Cady’s discovery of the sharp resonance of crystals. Archive for History of Exact Sciences, 62(5), 469-487. Retrieved from http://www.springerlink.com/content/d06306r21166632x/.