Causality constraints in gravitational theories

          @misc{ pirsa_PIRSA:14040116,
            doi = {10.48660/14040116},
            url = {https://pirsa.org/14040116},
            author = {},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {Causality constraints in gravitational theories},
            publisher = {Perimeter Institute},
            year = {2014},
            month = {apr},
            note = {PIRSA:14040116 see, \url{https://pirsa.org}}
          }