@article{702201,
title = {Algebraic methods in the theory of global properties of the oscillatory equations $Y^{\prime \prime }=Q(t)Y$
},
booktitle = {Equadiff IV},
series = {GDML\_Books},
publisher = {Springer-Verlag},
address = {Berlin},
year = {1979},
pages = {[35]-45},
mrnumber = {MR0535321},
zbl = {0405.34009},
url = {http://dml.mathdoc.fr/item/702201}
}
Borůvka, O. Algebraic methods in the theory of global properties of the oscillatory equations $Y^{\prime \prime }=Q(t)Y$
, dans Equadiff IV, GDML_Books, (1979), pp. [35]-45. http://gdmltest.u-ga.fr/item/702201/