[1] [CITE@en[RFC 1357 - A Format for E-mailing Bibliographic Records]], [TIME[2021-02-01T01:05:26.000Z]], [TIME[2021-03-13T09:57:25.986Z]] <https://tools.ietf.org/html/rfc1357>

[2] [CITE@en[RFC 1807 - A Format for Bibliographic Records]], [TIME[2021-01-24T13:06:15.000Z]], [TIME[2021-03-13T09:57:33.767Z]] <https://tools.ietf.org/html/rfc1807>