About the Court
Citation of ECJ cases
The Bluebook, 20th ed., does not mention that the Reports ceased publication in paper, but Rule 21.5.2 permits you to cite to Curia, another database or a commercial publication.
ECLI: The Bluebook 20th edition also does not cover the addition of the ECLI to the citation format. The Court's citation method now includes a neutral European Case-Law Identifier (ECLI). For example, ECLI:EU:C:2013:852 indicates the 852d decision delivered by the EU Court of Justice in 2013. See the Court's explanation of the new citation method and this post by Alison Shea. All cases with their ECLI are listed here.
Citation of judgments, Bluebook example (without the ECLI):
C-18/95, Terhoeve v. Inspecteur,  E.C.R. I-348. This case is published in the 1999 Reports of Cases Before the Court, Section I, at p. 348.
NOTE: As paper publications, the general Court reports ceased after 2011 and the reports of Staff Cases ceased after 2009. Starting with 2012 for the general Reports and 2010 for the Staff Cases, cases are published officially online on EUR-Lex and also on Curia, the court's website. See also two posts by Alison Shea here and here.
According to Curia, there has not been a separate Reports of Staff Cases since 1 September 2016. Staff cases are now part of the general Reports.
Curia has more details about the Reports, including criteria for which cases are published and which are not.