APA (7th ed.) Citation

Germany. Heer, Bibliothek für Zeitgeschichte (Germany), & Adam Matthew Digital (Firm). Siegfried. [publisher not identified].

Chicago Style (17th ed.) Citation

Germany. Heer, Bibliothek für Zeitgeschichte (Germany), and Adam Matthew Digital (Firm). Siegfried. [Elberfeld, Germany?]: [publisher not identified].

MLA (9th ed.) Citation

Germany. Heer, et al. Siegfried. [publisher not identified].

Warning: These citations may not always be 100% accurate.