1. A. V. Aho, J. E. Hopcroft, and J. D. Ullman, The Design and Analysis of Computer Algorithms, Addison-Wesley, Reading, MA, 1974.
2. The Width of a Chair
3. Chee K. Yap, Algorithmic motion planning, in Advances in robotics: Volume 1 (J. T. Schwartz and Chee K. Yap, eds.), Lawrence Erlbaum Assoc's, Hillsdale, NJ, 1987.