DEPENBROCK, M.; STEIMEL, A.; FOERTH, C.; HOFFMANN, F.; WEIDAUER, M.; KOCH, S. Speed-Sensorless Stator Flux-Oriented Control of Induction Motor Drives in Traction. Communications - Scientific letters of the University of Zilina, v. 3, n. 2-3, p. 68-75, 30 Sep. 2001.