I have got a cooperation and user agreement with Prof. Dr. Peter Klein from the Department of Wood Science (University of Hamburg). Since several years we work together with several partners with different backrounds, including Research/University Department of Wood Science University of Hamburg Federal Research Centre for Forestry and Forest Products Hamburg, Johann Heinrich von Thünen-Institut University of Natural Resources and Applied Life Sciences in Vienna, Austria Ecole Nationale Supérieure des Technologies et Industries du Bois in Epinal, France University of Applied Sciences and Arts Hildesheim/Holzminden/Göttingen University of Ljubljana in Ljubljana, Slovenia Museums | Collections Staatliches Institut für Musikforschung, Stiftung Preußischer Kulturbesitz, Berlin Münchner Stadtmuseum Museum für Kunst und Gewerbe Hamburg Kunsthistorisches Museum Wien, Austria National Music Museum, Vermillion, USA The Metropolitan Museum of Art, New York, USA Musikinstrumentenmuseum der Universität Leipzig Händel-Haus Halle Germanisches Nationalmuseum Nürnberg Musikkollegium Winterthur, Switzerland Geigenbaumuseum Mittenwald Maggini-Foundation Langenthal, Switzerland The Orpheon foundation, Museum of historical musical instruments, Austria Württembergisches Landesmuseum Stuttgart Tiroler Landesmuseum Innsbruck, Austria several violin makers several dealers of fine stringed instruments several private collectors several restorers