IT-Projekte in der öffentlichen Verwaltung - Analogien zum Outsourcing. - E. Ulrich Kriegel; Lutz Nentwig; Eric Siegeris (Software Management, 2004)

An integrated Collaboration Environment for Various Types of Collaborative Knowledge Work. - Frank Fuchs-Kittowski; Eric Siegeris (Int. J. e Collab., 2010)