1. Jansen, P.L. and Lorenz, R.D.: Accuracy Limitations of Velocity and Flux Estimation in Direct Field Oriented Induction Machines, Proc. EPE Conf., Brighton. UK, September 1993.
2. Zinger. D.S., Lipo, T.A., and Novotny, D.W.: Using Induction Motor Stator Windings to Extract Speed Information. Proc, IEEE-IAS Annual Meeting. San Diego, CA, October 1989.
3. Cuzner, R.M., Lorenz, R.D., and Novotny, D.W.: Application of Non-Linear Observers for Rotor Position Detection on an Induction Motor Using Machine Voltages and Currents, Proc. IEEE-IAS Annual Meeting. October 1990.
4. Ferrah, A., Bradley, K.G., and Asher G.M., Sensorless Speed Detection of Inverter Fed Induction Motors using Rotor Slot Harmonics and Fast Fourier Transform, PESC, 1992. pp. 280–286.
5. Schroedl, M.: Operation of the Permanent Magnet Synchronous Machine Without a Mechanical Sensor. Proc. Int. Conf. on Power Electronics and Variable Speed Drives. IEE, London, July 1990. pp. 51–56.