Bekker numbering or Bekker pagination is the standard form of citation to the works of Aristotle. It is based on the page numbers used in the Prussian Academy of Sciences edition of the complete works of Aristotle and takes its name from the editor of that edition, the classical philologist August Immanuel Bekker (1785-1871); because the Academy was located in Berlin, the system is occasionally referred to by the alternative name Berlin numbering or Berlin pagination.
Bekker numbers take the format of up to four digits, a letter for column 'a' or 'b', then the line number. For example, the beginning of Aristotle's Nicomachean Ethics is 1094a1, which corresponds to page 1094 of Bekker's edition of the Greek text of Aristotle's works, first column, line 1.
All modern editions or translations of Aristotle intended for scholarly readers use Bekker numbers, in addition to or instead of page numbers. Contemporary scholars writing on Aristotle use the Bekker number so that the author's citations can be checked by readers without having to use the same edition or translation that the author used.
While Bekker numbers are the dominant method used to refer to the works of Aristotle, Catholic or Thomist scholars often use the medieval method of reference by book, chapter, and sentence, albeit generally in addition to Bekker numbers.
Stephanus pagination is the comparable system for referring to the works of Plato.
The following list is complete. The titles are given in accordance with the standard set by the Revised Oxford Translation. Latin titles, still often used by scholars, are also given.
The Constitution of the Athenians (or Athenaiōn Politeia) was not included in Bekker's edition because it was first edited in 1891 from papyrus rolls acquired in 1890 by the British Museum. The standard reference to it is by section (and subsection) numbers.
Surviving fragments of the many lost works of Aristotle were included in the fifth volume of Bekker's edition, edited by Valentin Rose. These are not cited by Bekker numbers, however, but according to fragment numbers. Rose's first edition of the fragments of Aristotle was Aristoteles Pseudepigraphus (1863). As the title suggests, Rose considered these all to be spurious. The numeration of the fragments in a revised edition by Rose, published in the Teubner series, Aristotelis qui ferebantur librorum fragmenta, Leipzig, 1886, is still commonly used (indicated by R3), although there is a more current edition with a different numeration by Olof Gigon (published in 1987 as a new vol. 3 in Walter de Gruyter's reprint of the Bekker edition), and a new de Gruyter edition by Eckart Schütrumpf is in preparation.