In preparation of the lectures we have heavily borrowed graphical material from our cooworkers: Andrei Manolescu, Ingibjörg Magnúsdóttir, Sigurður I. Erlingsson, Llorrenc Serra, Detlef Heitmann, Markku Schwarz, Micael Tewe, Roman Krahne, Unnar Arnalds, Sveinn Ólafsson, Stephanie Reimann, Matti Manninen, Julia Gauger, and many others. In addition, we have borrowed figures from the textbooks of Kittel, Ashcroft and Mermin, and Gasiorowicz, and from the journals and web-material of the American Physical Society. Without this material the lectures would have been a few marks of chalk on the blackboard. We hope that all concerned authors will forgive us the occasional lack of a proper citation.
Vidar Gudmundsson
Daniela Pfannkuche