Ludwig Ritter von Köchel since undergone revisions. Mozart's works are often referred to by their K-numbers ("cf." opus number); for example, the "Jupiter" symphony, "Symphony No. 41" K. 551. Moreover, Köchel arranged Mozart's works into twenty-four categories, which were used by Breitkopf & Härtel when they published the first complete edition of Mozart's works from 1877 to 1910, a venture partly funded by Köchel. He also catalogued the works of Johann Fux. Ludwig Ritter von Köchel Ludwig Alois Friedrich Ritter von Köchel (; 14 January 1800 – 3 June 1877) was an Austrian musicologist, writer, composer, botanist and publisher. He is best known for
Term Catalogue omitting many; and refusing all under 1sh[illing] [in] Price; hath occasioned the Printing of this Catalogue: wherein those defects are rectified. Collected by, and printed for, the Booksellers of "London". A comparison of the numbers of titles listed in the late 17th and early 18th century term catalogues and numbers the English Short Title Catalogue provides justification for these complaints. The 161 catalogues printed between 1668 and 1711 show an increase in the number of titles. The average catalogue listed 109 books under 10 headings. Some catalogues had up to 13 headings; the minimum was six in the small catalogue