Citazione Stile APA (7a Edizione)

Knoll, J. H., & Siebert, H. (1967). Wilhelm von Humboldt: Politician and educationist. Inter Nationes.

Citazione stile Chigago Style (17a edizione)

Knoll, Joachim H., e Horst Siebert. Wilhelm Von Humboldt: Politician and Educationist. Bad Godesberg [Germany]: Inter Nationes, 1967.

Citatione MLA (9a ed.)

Knoll, Joachim H., e Horst Siebert. Wilhelm Von Humboldt: Politician and Educationist. Inter Nationes, 1967.