Question: Where was the university at which Donald N. Langenberg  served on the Board of Trustees at the located? 
Sentence (from "Donald N. Langenberg"): Langenberg has taught at the University of Oxford, the École Normale Supérieure, the California Institute of Technology, and the Technische Universität München and has served on the Board of Trustees at the University of the District of Columbia and the University of Pennsylvania.
Relevant evidence: Yes