74616272
Dec 29, 1994
Jul 9, 1996
construction materials, namely plastic and timber construction dowels for joining concrete segments, prefabricated concrete parts for underground construction and tunnel construction and concrete ring elements for tunnel excavation
Nonmetallic Building Materialstechnical advising and consultation in the field of tunnel excavation, building and construction, and providing access to a computer data base in the field of tunnel excavation, building and construction
Computer and Scientific