Al-Essa, Izzat M. “Capacitance-Voltage and Current-Voltage Characteristic for Multi- Walled Carbon Nanotubes Grown in Oxygen Atmosphere”. Iraqi Journal of Physics, vol. 7, no. 8, Dec. 2009, pp. 93-98, https://ijp.uobaghdad.edu.iq/index.php/physics/article/view/922.