Selected references:

• Library of Congress, Washington, D.C.
• The Strad, London
• Tarisio, London
• das Orchester, Schott Music, Mainz
• Scrollavezza & Zanrè, Parma
• dpunkt.verlag, Heidelberg
• Gmeiner publisher, Meßkirch
• mainbook publisher, Frankfurt
• Leinpfad publisher, Ingelheim
• German Book Trade Association (Frankfurt Book Fair), Frankfurt
• Wallraf-Richartz-Museum & Fondation Corboud, Cologne
• Suga & van Kollenburg
• IHK - Chamber of Commerce and Industry, Bonn
• DJG - German Justice Trade Union, Essen