Gravity degrees of freedom on a null surface

          @misc{ pirsa_PIRSA:17060022,
            doi = {10.48660/17060022},
            url = {https://pirsa.org/17060022},
            author = {Hopfmueller, Florian},
            keywords = {Other},
            language = {en},
            title = {Gravity degrees of freedom on a null surface},
            publisher = {Perimeter Institute},
            year = {2017},
            month = {jun},
            note = {PIRSA:17060022 see, \url{https://pirsa.org}}
          }