[5] Character sets: ISO 6937 vs ISO 8859, https://groups.google.com/g/comp.protocols.iso/c/07Kgb-joKiw/m/VWEoGlGnbrUJ
[6] Guide to the use of Character Sets in Europe, , http://std.dkuug.dk/cen/tc304/guide/gis6937.htm
[12] ETS 300 706 - Enhanced Teletext specification - ets_300706e01p.pdf, , https://www.etsi.org/deliver/etsi_i_ets/300700_300799/300706/01_60/ets_300706e01p.pdf#page=120
[13] Videotex (T.101) でもバリエーションが使われていました。
[15] T.107 も T.51String を定義していました。 T.107 PDF p.122
[17] KS X 1018-1:2004, KS X 1018-2:2004
[18] 00000001.PDF - 090.pdf, , https://itscj.ipsj.or.jp/ir/090.pdf
[19] n437.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/n437.pdf
[20] n454.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/n454.pdf
[21] 02n3323c.PDF - n481.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/n481.pdf
[22] n507.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/n507.pdf
[23] n512.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/n512.pdf
[24] 6937-981102.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/6937-981102.pdf
[25] 6937cd.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/6937cd.pdf
[26] WordPerfect - 6937wd1.wp - 6937wd1.pdf, , http://std.dkuug.dk/jtc1/sc2/wg3/docs/6937wd1.pdf