J. Tinbergen, 1991. "Solving the Most Urgent Problems First", in Michael Szenberg (ed.) 1993, Eminent Economists: Their Life Philosophies, Cambridge University Press, p. 279 (cambridge.org 20 Ekim 2012 tarihinde Wayback Machine sitesinde arşivlendi.).
J. Tinbergen, 1991. "Solving the Most Urgent Problems First", in Michael Szenberg (ed.) 1993, Eminent Economists: Their Life Philosophies, Cambridge University Press, p. 279 (cambridge.org 20 Ekim 2012 tarihinde Wayback Machine sitesinde arşivlendi.).