ハーン–バナッハの定理
“The strength of Hahn–Banach's Theorem”. Victoria Symposium on Non-standard Analysis. Lecture notes in Math.. 369. New York: Springer. pp. 203–248. ISBN 0-387-06656-X Citation from Foreman, M.; Wehrung, F. (1991). “The Hahn–Banach theorem implies the existence of a non-Lebesgue measurable set”. Fundamenta Mathematicae 138: 13–19. http://matwbn.icm.edu.pl/ksiazki/fm/fm138/fm13812.pdf.
↑ Brown, D. K.; Simpson, S. G. (1986). “Which set existence axioms are needed to prove the separable Hahn–Banach theorem?”. Annals of Pure and Applied Logic 31: 123–144. doi:10.1016/0168-0072(86)90066-7. Source of citation.