Counterexamples to a conjecture about bottlenecks in non-Tait-colourable cubic graphs
E. Steffen, Discrete Mathematics 161 (1996) 315.
LibreCat: /record/10197

Star chromatic numbers of graphs
E. Steffen, X. Zhu, Combinatorica 16 (1996) 439–448.
LibreCat: /record/10198

Tutte's 5-flow conjecture for graphs of non-orientable genus 5
E. Steffen, J. Graph Theory 22 (1996) 309–319.
LibreCat: /record/10199

Complexity results for the default- and autoepistemic logic
E. Steffen, in: E. Börger (Ed.), Computer Science Logic , Springer Berlin Heidelberg, 1992, pp. 339–352.
LibreCat: /record/10201