Feynmann Propagator in Spin Foam Quantum Gravity: Causality Without Time

          @misc{ scivideos_PIRSA:04100036,
            doi = {},
            url = {https://pirsa.org/04100036},
            author = {Oriti, Daniele},
            keywords = {},
            language = {en},
            title = {Feynmann Propagator in Spin Foam Quantum Gravity: Causality Without Time},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2004},
            month = {oct},
            note = {PIRSA:04100036 see, \url{https://scivideos.org/pirsa/04100036}}
          }