Decraene, B., Litkowski, S., Gredler, H., Lindem, A., Francois, P., and C. Bowers, "Shortest Path First (SPF) Back-Off Delay Algorithm for Link-State IGPs", RFC 8405, DOI 10.17487/RFC8405, June 2018, <https://www.rfc-editor.org/info/rfc8405>.