Earl, H. (2014). Christian Ingrao. Believe and Destroy: Intellectuals in the SS War Machine. The American Historical Review, Volume 119, Issue 3, June 2014, Pages 999–1000, https://doi.org/10.1093/ahr/119.3.999
Schidorsky, Dov (2007). «The Library of the Reich Security Main Office and Its Looted Jewish Book Collections». Libraries & the Cultural Record. 1. 42: 21–47. ISSN1932-4855. Besøkt 8. februar 2022. «Contemporary estimates do not specify whether they refer to all the books in the RSHA libraries or only to the Jewish collections. Stein, director of the library, estimated the number of books held in the library in 1941 at 500,000 to 1 million. Ernst Grumach, who headed the library's forced laborers, believed the total reached 2 to 3 million. Paul Dittel, appointed the library's director in 1943, indicated that in that year the library held only 200,000 to 300,000 volumes.»
Schidorsky, Dov (2007). «The Library of the Reich Security Main Office and Its Looted Jewish Book Collections». Libraries & the Cultural Record. 1. 42: 21–47. ISSN1932-4855. Besøkt 8. februar 2022. «Contemporary estimates do not specify whether they refer to all the books in the RSHA libraries or only to the Jewish collections. Stein, director of the library, estimated the number of books held in the library in 1941 at 500,000 to 1 million. Ernst Grumach, who headed the library's forced laborers, believed the total reached 2 to 3 million. Paul Dittel, appointed the library's director in 1943, indicated that in that year the library held only 200,000 to 300,000 volumes.»