The standard account of the 3,000 teppo is based on "Nobunagaki" (The Record of Nobunaga) by Hoan OZE and "Shinchoko-ki" (Biography of Nobunaga ODA) owned by the Ikeda family.
通説である鉄砲3000丁というのは小瀬甫庵本『信長記』や池田本『信長公記』が出典である。