Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{MASLO_1984__34_4_a10, author = {Regenda, J\'an}, title = {Oscillation criteria for differential equation $y\sp {(4)}+P(t)y''+R(t)y'+Q(t)y=0$}, journal = {Mathematica slovaca}, pages = {419--425}, publisher = {mathdoc}, volume = {34}, number = {4}, year = {1984}, mrnumber = {775251}, zbl = {0598.34028}, language = {en}, url = {http://geodesic.mathdoc.fr/item/MASLO_1984__34_4_a10/} }
Regenda, Ján. Oscillation criteria for differential equation $y\sp {(4)}+P(t)y''+R(t)y'+Q(t)y=0$. Mathematica slovaca, Tome 34 (1984) no. 4, pp. 419-425. http://geodesic.mathdoc.fr/item/MASLO_1984__34_4_a10/