The Official Journal (O.J.) of the European Union publishes the text of legislation and other official acts of the European Union. It contains treaties, all types of legislation, working papers, judgments of the European Court of Justice, proposals for legislation, and other official communications between EU institutions. Prior to 2003, this publication was called the Official Journal of the European Communities. Before 1973 when the United Kingdom and Ireland joined the EU, the O.J. was not published in English. Currently, the O.J. is published daily in all the official languages of the EU. To the U.S. researcher, the O.J. is a combination of the Statutes at Large, the U.S. Treaty series, the Code of Federal Regulations, the Federal Register and the Congressional Record.
There are 2 series in the Official Journal.
You can find more information about the structure of the Official Journal here.
According to EUR-Lex:
Effective 1 July 2013, the electronic edition of the OJ (e-OJ) is authentic and produces legal effects. However – due to an unforeseen and exceptional disruption of the Publications Office's IT systems – for the OJs listed here, it is the paper version that has legal value.
In such cases, the electronic version of the OJ is published on EUR‑Lex for information purposes only.
A regulation is generally cited by its number, then its year. In contrast, a directive is cited by its year first, then its number.
Example: Council Regulation No. 44/2001 of 22 December 2000 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters, 2001 O.J. (L 12) 1.
This Regulation is in the L Series of the OJ in the 2001 volume containing issue 12 for that year at page 1.
Example: First Council Directive 77/780 on the coordination of the laws, regulations and administrative provisions relating to the taking up and pursuit of the business of credit institutions, 1977 O.J. (L 322) 30.
Assuming you do not have a citation to the Official Journal, but only the year and number, select the "Year" as 1977 and the "Number of the OJ" as 322 on EUR-Lex.