German National Library of Economics

The German National Library of Economics (German: Deutsche Zentralbibliothek für Wirtschaftswissenschaften), abbreviated ZBW, is the world's largest library for economics. It also bears the suffix "Leibniz Information Centre for Economics" and is part of the Gottfried Wilhelm Leibniz Scientific Community (WGL). The headquarters of the ZBL is in Kiel, Germany with additional offices in Hamburg. It was established in 1919

More information on the Wikipedia page

The website, in German, is