Zhang, Z., Przygienda, T., Dolganow, A., Bidgoli, H., Wijnands, IJ., and A. Gulko, "Underlay Path Calculation Algorithm and Constraints for Bit Index Explicit Replication (BIER)", RFC 9272, DOI 10.17487/RFC9272, September 2022, <https://www.rfc-editor.org/info/rfc9272>.