[3] インターネットメールでの初出は RFC 733 で、 それ以前は似たような時間帯を表す文字列 (のみ) を特に注記なく定義しています。

[2] RFC 733 - Standard for the format of ARPA network text messages () https://tools.ietf.org/html/rfc733

The other remaining

two forms are taken from ANSI standard X3.51-1975. One allows

explicit indication of the amount of offset from GMT; the other

uses common 3-character strings for indicating time zones in

North America.

[1] RFC 822 - STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES () https://tools.ietf.org/html/rfc822

The other remaining two forms are taken

from ANSI standard X3.51-1975. One allows explicit indication of

the amount of offset from UT; the other uses common 3-character

strings for indicating time zones in North America.

ANSI. "Representations of Universal Time, Local Time Differen-

tials, and United States Time Zone References for Information

Interchange," X3.51-1975. American National Standards Insti-

tute: New York (1975).

[4] NCITS announces the Public Comment Period for the Withdrawal of ANSI X3.51:1994, Representations of Universal time, local time differentials, and United States time zone references for information interchange - INCITS (genb著, ) http://www.incits.org/news-events/press-releases/ncits-announces-the-public-comment-period-for-the-withdrawal-of-ansi-x3511994-representations-of-universal-time-local-time-differentials-and-united-states-time-zone-references-for-information-interchange

Washington D.C., March 1998 - NCITS (National Committee for Information Technology Standards) is announcing the public comment period for ANSI X3.51:1994. The public review extends from April 10, 1998 to June 9, 1998.

The scope of this standard is limited to the interchange of data among systems. This standard was not designed for (nor does it preclude) usage by humans as input to, or output from, data systems.

ANSI X3.51 is being withdrawn as it was incorporated in NCITS 310:1998, Information Technology -Representation of Time for Information Interchange.