The Thirty-nine Articles follow the naming convention of the Vulgate. Likewise, the Vulgate enumeration is often used by modern scholars, who nevertheless use the name Ezra to avoid confusion with the Greek and Slavonic enumerations: 1 Ezra, 2 Ezra, 3 Ezra, 4 Ezra, 5 Ezra and 6 Ezra.
The two books universally considered canonical (line 1 and 2 above) were originally one book titled Ezra or Esdras. In the early middle ages, the Hebrew and Latinbibles began to divide it into two books, which were titled Ezra and Nehemiah in Hebrew and 1 Esdras and 2 Esdras (and sometimes Nehemias) in Latin, respectively. Later on, most English translations followed the Hebrew titles while the Douay Rheims version followed the Vulgate. The Greek canon retained Ezra/Nehemia as a single book and called it Esdras B to distinguish it from Esdras A.
The latter book (line 3 above) does not form part of either the Hebrew or the Latin canon though it was often included in Latin manuscripts and editions of the Bible under the title 3 Esdras. The Douay Rheims version followed this title, while other English versions chose a separate numbering for apocryphical books and called it 1 Esdras (using the Greek form to differentiate the apocryphical book from the canonicalEzra). The Greek bible, which included the book placed it before Esdras B and thefore called it Esdras A.
Another non-canonical book (line 4 above) is contained in some Latin bibles as 4 Esdras and some Slavonic manuscripts as 3 Esdras. Except for the Douay Rheims version (which follows the Vulgate), most English versions containing this book call it 2 Esdras (again using the Greek form for the apocryphical book). The book is not included in the Greek Septuagint and complete copy of the Greek text has not survived, though it is quoted by the Church fathers. Due to its apocalyptic content, the book also has been called Esdras the Prophet, Apocalyptic Esdras or Jewish Apocalypse of Ezra. Because the most complete extant text is in Latin, the book is also called Latin Esdras.
The Latin version differs from other versions in that it contains additional opening and closing chapters, which are also called 5 Ezra and 6 Ezra by scholars.