APA (7th ed.) Citation

Helm, J. Archivmaterialien zu Johannes Helm, 1927-.

Chicago Style (17th ed.) Citation

Helm, Johannes. Archivmaterialien Zu Johannes Helm, 1927-.

MLA (9th ed.) Citation

Helm, Johannes. Archivmaterialien Zu Johannes Helm, 1927-.

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