Sotner, Roman, Jan Jerabek, Tomas Dostal, and Kamil Vrba. 2016. “Z-Copy Voltage Controlled Current Follower Differential Input Transconductance Amplifier in Controllable Biquadratic Band-Pass Filter”. Elektronika Ir Elektrotechnika 22 (4):32 - 36. https://doi.org/10.5755/j01.eie.22.4.15911.