The Ave Maria University choirs will sing music of Schbert and Mozart at the 10 a.m. Mass Sunday, Feb. 27, under the direction of assistant conductor Rebecca Ostermann.The Mass will be entirely sung, with a mix of choral singing and congregational singing led by the choir.The choirs will sing selections from Franz Schubert's Mass No. 3 in B-flat; from W. A. Mozart's Missa brevis in B-flat; and from Mozart's Missa brevis in G major. \n