APA (7th ed.) Citation

Doyle, A. C. (1973). Black Peter. The red-headed league. Grafisk Forlag [u.a.].

Chicago Style (17th ed.) Citation

Doyle, Arthur Conan. Black Peter. The Red-headed League. Copenhagen: Grafisk Forlag [u.a.], 1973.

MLA (9th ed.) Citation

Doyle, Arthur Conan. Black Peter. The Red-headed League. Grafisk Forlag [u.a.], 1973.