Universität zu Köln

Article

Bouhmadi-López, Mariam, Kiefer, Claus ORCID: 0000-0001-6163-9519 and Martín-Moruno, Prado ORCID: 0000-0001-8073-4896 (2019). Phantom singularities and their quantum fate: general relativity and beyond—a CANTATA COST action topic. General Relativity and Gravitation, 51 (10). Springer. ISSN 0001-7701

Kiefer, Claus ORCID: 0000-0001-6163-9519 and Wichmann, David (2018). Semiclassical approximation of the Wheeler–DeWitt equation: arbitrary orders and the question of unitarity. General Relativity and Gravitation, 50 (6). Springer. ISSN 0001-7701