KOTTMANN, C. Firmamentum angelicum: Allegorisches zum gotischen Chor St. Michael im Backnanger Stadtturm. Backnanger Jahrbuch, [S. l.], v. 7, p. 43–54, 1999. DOI: 10.53458/bjb.v7i.8991. Disponível em: https://journals.wlb-stuttgart.de/ojs/index.php/bjb/article/view/8991. Acesso em: 3 juli. 2024.