Technical Information
- A useful technical reference page for Crystals.
- http://www.icmfg.com/technicaldata.html

Bliley Electric Company History: The Early Years, 1930-1955
- History of the company that invented and patented the overtone crystal, etch-to-frequency and variable crystals. Source for ads, engineering bulletins, patents and manuals.
- http://www.bliley.net/XTAL/

Crystal multiplier chart
- WB6SZS, Eugene Rippen's comprehensive chart for crystal use on the HF, VHF and UHF bands.
- http://www.muchstuff.com/xtal-frq.htm

Crystal Oscillators
- From N6EV. Tube oscillator schematics, and discussion.
- http://www.qsl.net/n6ev/68-xtal.html

Crystal Info
- A handy historical chart of old crystal holders with dimensions, and suppliers.
- http://pages.cthome.net/fwc/XTAL.HTM

Crystal Grinding
- FT243 information compiled by Paul Carreiro, N6EV.
- http://www.qsl.net/n6ev/ft243.txt