[1] The MARC formats are standards for the representation and communication of bibliographic and related information in machine-readable form, and they are frequently used in library database systems.
Originally based on the Latin alphabet, from 1979 to 1983 the JACKPHY initiative expanded the repertoire to include Japanese, Arabic, Chinese, and Hebrew characters (among others), with the later addition of Cyrillic and Greek scripts.
The combining characters are not always stored in reverse order as Unicode normalization.
For example, to encode the U+4EBA CJK character (人) you will need the following bytes The \x1B\x24\x31 switches to EACC/CJK, and the \x21\x30\x64 corresponds to the U+4EBA.
[3] The following alternative C1 control code set is defined for bibliographic applications such as library systems.
MARC-8 uses the coding of NSB and NSE from this set, and adds some additional format effectors in locations not used by the ISO version; however, MARC 21 uses this control set only in MARC-8 records, not in Unicode-format records.