How to cite a primary document

What a citation must let the reader do

A citation should let a reader reach the same document, in the same version, from the official publisher. That needs four things: the issuing body, the official identifier, the date or version, and a link to the official source. The examples below show how official systems supply each one, using their own identifiers ^{1,2 3}.

Judgments

The European Case Law Identifier has five mandatory elements separated by colons: the ECLI prefix, the country code, the court code, the year and an ordinal number of up to 25 characters ¹. The e-Justice Portal gives ECLI:NL:HR:2009:384425 as a non-existent example ¹. The Council of the European Union invited member states and EU institutions to introduce it ¹.

CURIA lists EU cases by case number in the order they were lodged ². For England and Wales, link the judgment on Find Case Law, the official and free source ⁶.

Legislation and gazette notices

Name the version. legislation.gov.uk shows legislation as originally enacted or made and in revised form with later amendments applied ³. Changes not yet applied are listed under Changes to Legislation ³. A revised version can lag the law, so cite the version date shown.

For EU acts, cite the Official Journal. Only the electronic Official Journal is authentic and produces legal effects ⁴. The date in the header of a consolidated text on EUR-Lex is the date the latest amendment in that version becomes applicable ⁵.

For US regulations, the Federal Register prints rules as they are issued, and the Code of Federal Regulations holds the complete text by title, updated once a year ⁷.

Company filings

Cite the registry, the company's registered name and number, the form type and the filing date. EDGAR full text search covers all filings since 2001, including exhibits, so cite the exhibit if you quote one ⁸. For Companies House, link the filing history entry on the free register ⁹.

A checklist

• Issuing body, such as the court, parliament or registry ¹
• Official identifier, such as an ECLI or case number ^1,2
• Version: original, revised or consolidated, with its date ^3,5
• Link to the official publisher, not a copy site ⁴
• Date you accessed it, for pages that change ³