found: Klemperer, O. Die Kroll-Jahre [SR] p1988:booklet (Kroll Theatre; Kroll Opera)
found: Klemperer, O. The Kroll Oper years [SR] p1996:container (Staatskapelle Berlin)
found: Riemann Musik Lexikon, 12. Ausg.:Sachteil, p. 674 (Staatskapelle Bln (Unter d. Linden), 1735; Staatskapelle also played in the Krolloper, 1924-1931)
found: LC data base, 01-30-90(hdg.: Krolloper)
found: New Grove, v. 2, p. 575(In 1927 Prussian Ministry of Culture established a branch of the Berlin Staatsoper, the Staatsoper am Platz der Republik; played in the Kroll Theatre; Kroll Opera closed after four seasons in July 1931)
found: Dülfer, M. Entwurf zum Koeniglichen Opernhause in Berlin, 1912?:p. 1 (to be located on the Königsplatz in Berlin)
found: Warrack, J.H. The Oxford dic. of opera, 1992(under Berlin: in 1896 a new opera-house was planned ... in the Königsplatz; opened in 1924; the Kroll Oper (officially named Oper am Platz der Republik); closed in 1931, became home of the Reichstag in 1933)
notfound: Oper am Königsplatz (Berlin, Germany). Oper am Königsplatz, 16 Dez. 1924: t.p. (Oper am Königsplatz)