Creating and Testing Textbooks for Secondary Schools. - Karin Freiermuth; Juraj Hromkovic; Björn Steffen (ISSEP, 2008)

The Steiner Tree Reoptimization Problem with Sharpened Triangle Inequality. - Hans-Joachim Böckenhauer; Karin Freiermuth; Juraj Hromkovic; Tobias Mömke; Andreas Sprock; Björn Steffen (CIAC, 2010)

Steiner tree reoptimization in graphs with sharpened triangle inequality. - Hans-Joachim Böckenhauer; Karin Freiermuth; Juraj Hromkovic; Tobias Mömke; Andreas Sprock; Björn Steffen (J. Discrete Algorithms, 2012)