How the ISIL is constructed?

The ISIL is a variable length identifier. It consists of a maximum of 16 characters. The permitted characters are: Arabic numerals 0 to 9, unmodified lettres from the basic Latin alphabet and the special marks solidus (/), hyphen-minus (-) and colon (:).

An ISIL is made up of two components: a prefix and a library identifier, in that order, seperated by a hyphen-minus.
The prefix is either a two character country code or a non-country code, consisting of one, three, or four characters or digits (but not special marks).

The non-country code prefixes are registered at a global level with the ISIL Agency, as are the national ISIL centres, which are responsible for a certain country code.

The ISIL standard allows the national ISIL centres a high level of autonomy in the organization of the identifiers for the registered institutions. In Switzerland six-digit sequence numbers without further meaning, followed by a hyphen-minus and a check digit similar to ISBN and ISSN, are used.

Example for the Swiss Literary Archives: CH-000015-0

Last modification 01.08.2011

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