@article{AFST_2007_6_16_3_427_0,
     author = {Charles Boubel},
     title = {On the holonomy of {Lorentzian} metrics},
     journal = {Annales de la Facult\'e des sciences de Toulouse : Math\'ematiques},
     pages = {427--475},
     publisher = {Universit\'e Paul Sabatier, Institut de Math\'ematiques},
     address = {Toulouse},
     volume = {Ser. 6, 16},
     number = {3},
     year = {2007},
     doi = {10.5802/afst.1156},
     mrnumber = {2379049},
     language = {en},
     url = {https://afst.centre-mersenne.org/articles/10.5802/afst.1156/}
}