A Multi-level Planning and Navigation System for a Mobile Robot: A First Approach to HILARE. - Georges Giralt; Ralph P. Sobek; Raja Chatila 001 (IJCAI, 1979)

A Robot Planning Structure Using Production Rules. - Ralph P. Sobek (IJCAI, 1985)

Integrated planning and execution control for an autonomous mobile robot. - Ralph P. Sobek; Raja Chatila 001 (Artif. Intell. Eng., 1988)

Using Learning to Recover Side-Effects of Operators in Robotics. - Ralph P. Sobek; Jean-Paul Laumond (ML, 1989)