R. Sotner, J. Jerabek, W. Jaikla, N. Herencsar, K. Vrba, and T. Dostal, “Novel Oscillator Based on Voltage and Current-Gain Adjusting Used for Control of Oscillation Frequency and Oscillation Condition”, ELEKTRON ELEKTROTECH, vol. 19, no. 6, pp. 75–80, Jun. 2013, doi: 10.5755/j01.eee.19.6.4567.