@book{Fridrich2012, editor = {Fridrich, Christian and Heinrich, Kati and Jekel, Thomas and Keller, Lars and Koller, Alfons and Lieb, Gerhard and Pichler, Herbert}, year = {2012}, title = {GW-Unterricht Nr. 124}, address = {Graz, Innsbruck, Linz, Salzburg, Wien} }