Martin, William McChesney. Letter to John W. Snyder, Secretary of the Treasury, Box 11, Folder 4, William McChesney Martin, Jr., Papers. https://fraser.stlouisfed.org/content/?item_id=456771&filepath=/files/docs/historical/martin/11_04_19470627.pdf, accessed on May 22, 2018.
Regarding change of interest rate.
- Board of Governors of the Federal Reserve System, Federal Reserve Board
- Meltzer's History of the Federal Reserve - Primary Sources