Mepụta ụdị nkebi ahịrịokwu a'' Ọfịs Na-ahụ Maka Ọpụpụ German site na Neurath ruo Ribbentrop''.
N'ezie, nsụgharị dị mgbagwoju anya nke ahịrịokwu ahụ bụ "' 'Germany Foreign Office from Neurath to Ribbentrop '' na Gordon A. Craig na Felix Gilbert (ed. ' 'Ndị Diplomat 1919 - 39' '".