To add a video for Michael Haller / Missa undecima in honorem Sancti Henrici imperatoris, Confessoris, Op.24, just enter the video‘s YouTube link:
example) https://www.youtube.com/watch?v=XXXXXXXXXXX
Search YouTube for Michael Haller / Missa undecima in honorem Sancti Henrici imperatoris, Confessoris, Op.24