Symphony, K. 75 (Mozart) works from this time period, such as the K. 97 symphony, the autograph, which was in the possession of Breitkopf & Härtel, was destroyed during World War II. Mozart's authorship therefore remains uncertain. Most professionals consider the work authentic. The Alte Mozart-Ausgabe (published 1879–82) gives the numbering sequence 1–41 for the 41 numbered symphonies. The unnumbered symphonies (some, including K. 75, published in supplements to the Alte-Mozart Ausgabe until 1910) are sometimes given numbers in the range 42 to 56, even though they were written earlier than Mozart's Symphony No. 41 (written in 1788). The symphony K. 75 is given
Köchel catalogue and Georges de St. Foix) reassigned a number of works from the original K appendices into the main catalogue by interpolating new numbers into the main sequence with a lower-case letter suffix. In K some of these were reassessed in the light of scholarship since 1937 and returned to the re-worked appendices: For example, the Divertimento for Wind Octet in E♭ was numbered Anh. 226 in K; Einstein placed it in the K main catalogue as K. 196e, between K. 196 and K. 197; K reassigned it again to the 'doubtful' appendix C as Anh. C 17.01. Some works in