title: PREFACE.
authors.affiliation: Bundesamt für Eich- und Vermessungswesen, Arltgasse 35, A-1160 Wien, Austria. Electronic address: Franz-Josef.Maringer@bev.gv.at.
authors.forename: Franz Josef
authors.initials: FJ
authors.lastname: Maringer
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, d-38116 Braunschweig, Germany. Electronic address: Dirk.Arnold@ptb.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Arnold
authors.affiliation: Kievermondeveld 74, B-2440 Geel, Belgium. Electronic address: Uwe.Watjen@telenet.be.
authors.forename: Uwe
authors.initials: U
authors.lastname: Wätjen