"Software Pioneers: Contributions to Software Engineering: Programme Development by Stepwise Refinement". Book edited by Manfred Broy and Ernst Denert, June 27, 2002.
Peter Drucker, Alan Kantrow, Rick Wartzman, Julia Kirby (2016). “Get the Right Things Done: The Drucker Collection (6 Items)”, p.33, Harvard Business Review Press
Advice to a newly appointed colonial governor ignorant in the law, in John Lord Campbell 'The Lives of the Chief Justices of England' (1849) vol. 2, ch. 40