IMSLP Forums

The item: Duo concertante in E-flat major, Kor.40 (Tomasini, Luigi) found at
http://imslp.org/wiki/Duo_concertante_i ... ,_Luigi%29

turns out to be one of 3 Duos concertants found at:
http://imslp.org/wiki/3_Duos_Concertant ... ,_Luigi%29

I don't have the authority to amalgamate these items.

No need to merge. The 3 Duos is actually a collection page, which also appears under the composer's main category tab for convenience. Once all three of the items in the collection are added as individual works, the collection page will be relegated to appear beneath the Collections header.