An overview of the CITE Object URN notation

CITE Object URNs (or “CITE URNs” for short) are part of the CITE architecture. They provide the permanent canonical references to discrete objects (whether physical or notional), and are used by the CITE Collection service to identify and retrieve digital representations of those objects.

CITE URNs are a kind of Uniform Resource Name (URN). To quote from RFC 2141,

Uniform Resource Names (URNs) are intended to serve as persistent, location-independent, resource identifiers.

Semantics of a CITE URN

CITE URNs identify a unique object in a set of similarly structured objects — a specific manuscript in a set of manuscripts, a specific folio in the the set of folios in a specific manuscript, a specific named individual in a set of people, are all examples of objects that can be identified by CITE Object URNs.

Syntax of a CITE URN

URNs always begin with the string urn: followed by a protocol identifier. We use the identifier cite for our protocol.

Colons separate the top-level elements of a CTS URN: any use of a semicolon as a data value must therefore be escaped. The top-level elements are:

1.  urn name space (required: always cite)
2.  cite namespace (required: a value registered with the Scaife Digital Library list of CTS namespaces)
3.  work identifier (required: a value that can be resolved to a unique URI)
4.  collection and object identifiers

The general structure of a CITE URN is therefore


The fourth component is formatted as two dot-separated parts. The first identifies the collection, and must be a value recognized by the registry identified by the CITE namespace component; the second is an identifier for the specific object that is guaranteed to be unique with the specified collection.


The Homer Multitext project works with a number of CITE Collections. These are in the CITE namespace, identified in the following example by the abbreviation hmt. (This means that a Collection service recognizing the abbreviation can expand it to the full URI

One collection in that namespace is a collation of all folio sides in a manuscript in Venice, Marciana 454, known as the “Venetus A.” The identifier for this collection is msA, and a valid CITE URN to identify the entire collection would therefore be


Within the collection, folio twelve recto is identified by the object identifier msA-12r. The CITE URN for folio twelve recto is therefore