1. Electro-principles I, ETEC 1120. http://www.technology.niagarac.on.ca
2. Electronic devices and circuits, engineering sciences 154, Diode i–v characteristics. http://people.deas.harvard.edu
3. Varactor diode, American microsemiconductor. http://www.americanmicrosemi.com
4. Thyristors, All about circuits. http://www.allaboutcircuits.com
5. Bilateral trigger diacs, thyristor product catalog, Teccor electronics. http://www.teccor.com