PortalU® - a Tool to Support the Implementation of the European Environmental Information Directive. - Thomas Vögele; Martin Klenke; Fred A. Kruse; Hanno Lehmann; Christiane Giffei (EnviroInfo (2), 2007)

Shaping PortalU®/InGrid® to Meet the INSPIRE Requirements - First Experiences and Some Considerations on How to Efficiently Organize the German Spatial Data Infrastructure as INSPIRE Node. - Martin Klenke; Fred A. Kruse; Stefanie Uhrich; Christiane Giffei; Sybille Peters (EnviroInfo, 2008)

Einbindung von Kommunen in das Umweltportal Deutschland am Beispiel des Kommunalen PortalU® Niedersachsens. - Fred A. Kruse; Martin Klenke; Stefanie Uhrich; Christiane Giffei; Sybille Peters (EnviroInfo, 2008)

The Information Technology of the German Environmental Information Portal PortalU® as Tool for the European Level? - Stefanie Uhrich; Fred A. Kruse; Martin Klenke; Christiane Giffei; Sybille Peters (EnviroInfo, 2008)