In 1910 and 1913, Swedish Mathematician Gustav Eneström completed the first comprehensive survey of Euler's works. He counted and enumerated 866 distinct works, including books, journal articles, and some letters he deemed to be especially important. Each of these was given a number, E1  E866, which are now referred to as "Eneström number." Much like Köchel's Verzeichnis of Mozart's work, this gives scholars a quick way to identify Euler's writings, and most historical scholars refer to the works of Euler by their Enestrom number when describing them.
The complete list was originally published as Die Schriften Eulers chronologisch nach den Jahren geordnet, in denen sie verfasst worden sind (The Writings of Euler, ordered by the year in which he wrote them) in the 1913 Edition of the Jahresbericht de Deutschen MathematikerVereinigung.









