1. A. Nentwich, M. Schneeberger, A. Szeless, H. Wi1k, Photovoltaic Activities of the Austrian Electric Utilities — Projects and Experiences, poster presentation, 9-th European Photovoltaic Solar Energy Conference, Freiburg, Sept. 25 – 29, 1989
2. World Renewable Energy Congress;A Nentwich,1990
3. Internationales Sonnenforum;A Szeless,1990