1. Analysis of pulse duration sampled-data systems with linear elements;Andeen;IRE Trans. AC,1960
2. Stability conditions of PWM systems through the second method of Lyapunov;Kadota;IRE Trans. AC,1961
3. Analysis of PWM control systems;Delfeld;IRE Trans. on AC,1961
4. Stability and graphical analysis of first order PWM sampled data regulator systems;Polak;IRE Trans. AC,1961
5. Stability study of PWM feedback systems;Jury;Trans. ASME,1964