Johannsen, G. K., & Kraft, H. H. (1937). Germany's colonial problem; the necessity for redistributing the world's raw material resources: Facts and arguments supporting Germany's claim to the return of her colonies. T. Butterworth ltd.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Johannsen, Gustav Kurt, و Heinrich Helmut Kraft. Germany's Colonial Problem; the Necessity for Redistributing the World's Raw Material Resources: Facts and Arguments Supporting Germany's Claim to the Return of Her Colonies. London: T. Butterworth ltd, 1937.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Johannsen, Gustav Kurt, و Heinrich Helmut Kraft. Germany's Colonial Problem; the Necessity for Redistributing the World's Raw Material Resources: Facts and Arguments Supporting Germany's Claim to the Return of Her Colonies. T. Butterworth ltd, 1937.