This primary source comes from the Collection FDR-MR: Papers as President, Map Room File.
National Archives Identifier:
194854Full Citation: Winston Churchill to Franklin D. Roosevelt; 05/15/1940; Collection FDR-MR: Papers as President, Map Room File. [Online Version, https://www.docsteach.org/documents/document/1-winston-churchill-to-franklin-d-roosevelt, April 19, 2024]