@article{10_4064_ap_25_2_145_148,
     author = {P. Besala},
     title = {On partial differential inequalities of the first order},
     journal = {Annales Polonici Mathematici},
     pages = {145--148},
     publisher = {mathdoc},
     volume = {25},
     number = {2},
     year = {1971},
     doi = {10.4064/ap-25-2-145-148},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-25-2-145-148/}
}