1. 1. M. K. Ghartemani, H. Karimi, M. R. Iravani. “A magnitude phase- locked loop system based on estimation of frequency and in-phase quadrature-phase amplitudes”. IEEE Trans.Industrial Electronics, Vol. 51, No.2, pp. 511-517, 2004.
   2. A. K. Ziarani, M. Karimi Ghartemani.“On the equivalence of three independently developed phaselocked loops,” IEEE Trans. on Automation Control, Vol. 50, No.12, pp. 2021-2027, 2005.
   3. Brijesh M. Patel, Kalpesh J.Chudasma, Hardik A.Shah. “Simulation of Single Phase Inverter using PSIM Software for Solar P.V. System give Constant Output Voltage at Different Solar Radiation”. International Journal of Emerging Trends in Electrical and Electronics (IJETEE – ISSN: 2320-9569) Vol. 4, Issue. 1, June-2013.
   4. Haroon Rashid ,Md. Mamun, Md. Syedul Amin, Hafizah Husain. “Design of a Low Voltage Schmitt Trigger in 0.18 m CMOS Process With Tunable Hysteresis”. Modern Applied Science; Vol. 7, No. 4; 2013. Published by Canadian Center of Science and Education.
   5. Annu Khurana, Anshul Saxena, Neeraj Jain. “Evaluation of low power Schmitt Trigger for communication system”. International Research Journal of Engineering and Technology (IRJET),Volume: 02 Issue: 05 ,Aug-2015.
   6. Daniel Abramovitch. “Phase-Locked Loops: A Control Centric Tutorial”. June 24, 2003.
   7. Mr. Rajan J. Devi, Miss. Supriya S. Kadam. “Phase Locked Loop for synchronization of Inverter with Electrical grid: A Survey”. International Journal of Engineering Research & Technology (IJERT), Vol. 4, Issue 02, February-2015.
   8. L. Rolim, D. Costa, M. Aredes. “Analysis and software implementation of a robust synchronizing PLL circuit based on the pq theory”. IEEE Trans. Industrial Electronics, Vol. 53, No.6, pp. 1919-1926, 2006.
   9. Masoud Karimi-Ghartemani and M. Reza Iravani, “A Nonlinear Adaptive Filter for Online Signal Analysis in Power Systems: Applications” IEEE transactions on power delivery, vol. 17, no. 2, pp.617- 622, April 2002.