| 2009 | LATA | Reoptimization of Traveling Salesperson Problems: Changing Single Edge-Weights. | Tobias Berg, Harald Hempel |
| 2008 | COCOON | Approximating Alternative Solutions. | Michael Krger, Harald Hempel |
| 2006 | ISAAC | Inverse HAMILTONIAN CYCLE and Inverse 3-D MATCHING Are coNP-Complete. | Michael Krger, Harald Hempel |
| 2004 | MFCS | All Superlinear Inverse Schemes Are coNP-Hard. | Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel |
| 2001 | COCOON | Algebraic Properties for P-Selectivity. | Lane A. Hemaspaandra, Harald Hempel, Arfst Nickelsen |
| 1999 | STACS | Extending Downward Collapse from 1-versus-2 Queries to j-versus-j+1 Queries. | Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel |
| 1999 | WG | On Claw-Free Asteroidal Triple-Free Graphs. | Harald Hempel, Dieter Kratsch |
| 1997 | CIAC | R | Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel |
| 1997 | FCT | Query Order in the Polynomial Hierarchy. | Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel |
| 1997 | STACS | A Downward Translation in the Polynomial Hierarchy. | Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel |
| 1997 | STACS | The Operators min and max on the Polynomial Hierarchy. | Harald Hempel, Gerd Wechsung |