He completed his Ph. D. dissertation on Ludwig Mies van der Rohe in 1981 .
Tegethoff studied art history , urban design , economic history and social history at the University of Bonn and Columbia University , New York .
Tegethoff completed Tegethoff 's Ph. D. dissertation on Ludwig Mies van der Rohe in 1981 .
Tegethoff studied art history , urban design , economic history and social history at the University of Bonn and Columbia University , New York .