@article{ENMA_1991__4_186560,
     author = {I. Kupka},
     title = {Introduction of the {Theory} of {Systems.} / {I.} {Kupka.}},
     journal = {Ensaios Matem\'aticos},
     pages = {5--108},
     publisher = {mathdoc},
     volume = {4},
     year = {1991},
     zbl = {1196.93001},
     url = {http://geodesic.mathdoc.fr/item/ENMA_1991__4_186560/}
}