APA (7th ed.) Citation

Helwing, B., & Helwing, B. (2011). Alexander Langsdorff in Persien.

Chicago Style (17th ed.) Citation

Helwing, Barbara, and B. Helwing. Alexander Langsdorff in Persien. 2011.

MLA (8th ed.) Citation

Helwing, Barbara, and B. Helwing. Alexander Langsdorff in Persien. 2011.

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