Jie Jin ,  Current-Mode Resistorless SIMO Universal Filter and Four-Phase Quadrature Oscillator.   journal   = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2013, vol. 74(2). 216 - 221
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/9996922.