[1] [CITE@en[RFC 4550: Internet Email to Support Diverse Service Environments (Lemonade) Profile]], [TIME[2023-03-24T05:20:34.000Z]] <https://www.rfc-editor.org/rfc/rfc4550.html>

[2] [CITE[RFC Errata Report » RFC Editor]], [TIME[2023-03-24T05:23:22.000Z]] <https://www.rfc-editor.org/errata/rfc4550>

[3] [CITE@en[RFC 5550: The Internet Email to Support Diverse Service Environments (Lemonade) Profile]], [TIME[2023-03-24T05:24:11.000Z]] <https://www.rfc-editor.org/rfc/rfc5550.html>