@article{SIGMA_2019_15_a99,
     author = {Teresa Crespo and Zbigniew Hajto},
     title = {Picard{\textendash}Vessiot {Extensions} of {Real} {Differential} {Fields}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2019},
     volume = {15},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2019_15_a99/}
}