APA (7th ed.) Citation

Freytag, R. (1930). Der erste Luftballon in Regensburg.

Chicago Style (17th ed.) Citation

Freytag, Rudolf. Der Erste Luftballon in Regensburg. Regensburg, 1930.

MLA (9th ed.) Citation

Freytag, Rudolf. Der Erste Luftballon in Regensburg. 1930.

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