Competitive Searching in Polygons - Beyond Generalised Streets. - Amitava Datta; Christoph A. Hipke; Sven Schuierer (ISAAC, 1995)

How to Find a Point on a Line Within a Fixed Distance. - Christoph A. Hipke; Christian Icking; Rolf Klein; Elmar Langetepe (Discret. Appl. Math., 1999)