Recommended Reading about Piezoelectricity  
   PIEZO SYSTEMS, INC.
   http://www.piezo.com/reading.html

Introduction to Bending Elements  
   Piezo Systems Corp.
   http://www.piezo.com/bendedu.html

Smart Material, Corp. (Germany)  
   Advanced piezoelectric Materials and Components
   http://www.smart-material.com

Ferroelectrics Newsletter  
   
   http://www.sp.nps.navy.mil/projects/ferro/ferro.html

Theory and Applications of Piezo Ceramic Actuators and PZT NanoPositioning Systems  
   Physikinstrumente (Germany) - very good information about piezo actuators and positioning systems.
   http://www.physikinstrumente.com/tutorial/index.html

The Crystal Consortium Ltd.  
   conducts research into optoelectronics, piezoelectrics, and scintillators.
   http://www.crystalconsortium.co.uk

NPL: Sensors & Functional Materials Group - Publications about piezoelectric materials  
   the UK's national standards laboratory, who look after the basic units of measurement such as time, mass and length which ensure consistency and traceability of measurements.
   http://www.npl.co.uk/npl/cmmt/functional/publications.html