https://app.knowbase.one/vault/rfc/docid/1281
RFC1138: Mapping between X.400(1988) / ISO 10021 and RFC 822
Network Working Group S. Kille Request for Comments 1138 University College London Updates: RFCs 822, 987, 1026 December 1989 Mapping between X.400(1988) / ISO 10021 and RFC 822 Status of ...
https://app.knowbase.one/vault/rfc/docid/1675
RFC1496: Rules for downgrading messages from X.400/88 to X.400/84 when MIME content-types are present in the messages
Network Working Group H. Alvestrand Request for Comments: 1496 SINTEF DELAB Updates: 1328 J. Romaguera NetConsult AG ...