Letwin, W., Child, J., & Culpeper, T. (1959). Sir Josiah Child, merchant economist, with a reprint of Brief observations concerning trade and interest of money, 1668. Baker Library, Harvard Graduate School of Business Administration.

Letwin, William, Josiah Child, и Thomas Culpeper. Sir Josiah Child, Merchant Economist, with a Reprint of Brief Observations Concerning Trade and Interest of Money, 1668. Boston: Baker Library, Harvard Graduate School of Business Administration, 1959.

Letwin, William, et al. Sir Josiah Child, Merchant Economist, with a Reprint of Brief Observations Concerning Trade and Interest of Money, 1668. Baker Library, Harvard Graduate School of Business Administration, 1959.