@article{RLINA_1979_8_66_5_a12,
     author = {Grioli, Antonio Claudio and Balli, Raffaele},
     title = {Comparison between optical and totally geodesic coordinates in general relativity in connection with the first two {Cauchy-Green} tensors},
     journal = {Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali},
     pages = {396--401},
     publisher = {mathdoc},
     volume = {Ser. 8, 66},
     number = {5},
     year = {1979},
     zbl = {0472.53040},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RLINA_1979_8_66_5_a12/}
}