MLA
Luther, Martin, 1483-1546. De servo arbitrio Martini Lutheri, ad Desiderium Erasmum Roterodamu[m].. 1526. Richard C. Kessler Reformation Collection. Pitts Theology Library. https://digital.library.emory.edu/purl/931qfttgm6-cor.
APA, 6th edition
Luther, Martin, 1483-1546. (1526)[De servo arbitrio Martini Lutheri, ad Desiderium Erasmum Roterodamu[m].]. Richard C. Kessler Reformation Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/931qfttgm6-cor.
Chicago
Luther, Martin, 1483-1546, De servo arbitrio Martini Lutheri, ad Desiderium Erasmum Roterodamu[m]., 1526, Richard C. Kessler Reformation Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/931qfttgm6-cor.