⁸⁵Voir Helge KRAGH. « Is The Universe Expanding? Fritz Zwicky And Early Tired-Light Hypotheses ». In : Journal of Astronomical History and Heritage 20.01 (mars 2017), p. 2-12. URL : https://engine.scichina.com/doi/10.3724/SP.J.1440-2807.2017.01.01 (visité le 11/09/2023).