1. A versatile voltage controlled three phase oscillator;Kaplan;IEEE Trans.,1979
2. A simple three-phase variable-frequency oscillator;Rahman;Int. J. Electron.,1982
3. A novel three-phase reference sinewave generator for PWM invertors;Ramamurti;IEEE Trans.,1982
4. Continuous and switched-capacitor multiphase oscillators;Mikhael;IEEE Trans.,1984
5. Active-R multiphase oscillators;Abuelma'atti;IEEE Trans.,1984