APA (7th ed.) Citation

Helbing, H. Archivmaterialien zu Hugo Helbing, 1863-1938.

Chicago Style (17th ed.) Citation

Helbing, Hugo. Archivmaterialien Zu Hugo Helbing, 1863-1938.

MLA (9th ed.) Citation

Helbing, Hugo. Archivmaterialien Zu Hugo Helbing, 1863-1938.

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