How to measure the accessibility maturity of organizations—A survey on accessibility maturity models for higher education oleh Nadine Auer, Nadine Auer, Samira Kalemba, Christin Stormer, Ann-Katrin Boehm, Hakan Cetin, Anja Gutjahr, Franziska Neumann, Verena Kersken, Gerhard Weber, Gottfried Zimmermann