@article{10_4064_ap_19_2_201_205,
     author = {S. P. Hastings},
     title = {On the existence of a solution of a system ẋ= f(t, x) which remains in a given set},
     journal = {Annales Polonici Mathematici},
     pages = {201--205},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {1967},
     doi = {10.4064/ap-19-2-201-205},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-19-2-201-205/}
}