@unpublished{TUW-121064, author = {Pfeifer, Norbert}, title = {DSM/DTM Filtering}, year = {2007}, note = {invited; talk: 2nd ISPRS WG VI/5{\&}SC Summer School ''Theory and Application of Laser Scanning'', Ljubljana, Slowenien; 2007-07-01 -- 2007-07-07} }