Robust Sliding-mode Control of Nine-link Biped Robot Walking. - Spyros G. Tzafestas; Thanassis E. Krikochoritis; Costas S. Tzafestas (J. Intell. Robotic Syst., 1997)

Modeling and control of an omnidirectional mobile robot. - Spyros G. Tzafestas; Thanassis E. Krikochoritis; A. Melfi (Advanced Network Enterprises, 2000)