Jansen, Christian R.: Udenrigsministerium og privat diplomati – Omkring handelsaftalen med England af 19. November 1915 ("Ministry of Foreign Affairs and private diplomacy - About the trade agreement with England of 19. November 1915”), in: : Erhvervshistorisk årbog (Danish yearbook of business history), Copenhagen; Aarhus 1971 Statens Arkiver; Erhvervsarkivet.