The Official Journal of the European Union is "the official compendium of EU legal acts" (EUR-Lex FAQ). It is published every day from Tuesday to Saturday inclusive, in all official languages of the EU. Prior to Feb. 1, 2003, it was called the Official Journal of the European Communities.
Official edition: Council Regulation (EU) No. 216/2013, 7 March 2013, on the electronic publication of the Official Journal of the European Union, 2013 O.J. (L 69) 1, provides that, from 1 July 2013, only the Official Journal published in electronic form on EUR-Lex shall be authentic and shall produce legal effects. If, due to unforeseen and exceptional disruption of the information system, the electronic publication of the O.J. is temporarily not possible, then the print edition will be authentic and produce legal effects. See this list of O.J. issues for which the paper version has legal value. Use CheckLex to verify the electronic signature of an O.J. issue.
Citation: See also Bluebook Rule 21.9. Because page numbering starts over with page 1 in each daily issue, it is necessary to know the year of publication to find an O.J. issue with ease. Examples: 2001 O.J. (L1) 10 [the first issue of the L Series for 2001, at page 10]; 2000 O.J. (C371) 2 [the 371st issue of the C Series for 2000, at page 2].