As advance information please find here a selection of papers related to various topics on terrain models and modes of interactivity. All documents are available for download as PDF-files (Adobe Acrobat format):

References (selection, 140 kB)
Terrain Models I (220 kB)
Terrain Models II (shapes, 150 kB)
(optionally high resolution DIN A3, 230 kB:  )
Terrain Models III (software, 230 kB)
Large Scale Terrain Models 
(example Switzerland, 100 kB)