InGrid 1.0 - The Nuts and Bolts of PortalU. - Martin Klenke; Fred A. Kruse; Hanno Lehmann; Thomas Riegel; Thomas Vögele (EnviroInfo, 2006)

Easy Access to Environmental Information with PortalU. - Thomas Vögele; Martin Klenke; Fred A. Kruse; Hanno Lehmann; Thomas Riegel (EnviroInfo, 2006)

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)