Lee, Y., Zheng, H., Gonzalez de Dios, O., Lopez, V., and Z. Ali, "Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE Usage in GMPLS-Controlled Networks", RFC 9504, DOI 10.17487/RFC9504, December 2023, <https://www.rfc-editor.org/info/rfc9504>.