Westerman, Gerhart.Knauers Opernführer. Mit einem Geleitwort von Hans Knappertsbusch.Th. Knauer Nachf. Verlag, München 1952.
8o. Clothbinding (hardbouns). With a dustjacket in a bad condition many tears and loss of paper. Else godd condition. Photoillustrated in black and white. 541 pages. Text in German.