Bhaba Priyo Das and  Neville Watson and  Yonghe Liu,  Simulation of Voltage Controlled Tunable All Pass Filter Using LM13700 OTA.   journal   = {International Journal of Computer and Systems Engineering}, [online]. World Academy of Science, Engineering and Technology.
    August 2010, vol. 44(8). 1199 - 1203
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/8924.