@article{700084,
     title = {Oscillation in linear differential equations},
     booktitle = {Proceedings of Equadiff III},
     series = {GDML\_Books},
     publisher = {Univ. J. E. Purkyn\v e - P\v r\'\i rodov\v edeck\'a fakulta},
     address = {Brno},
     year = {1973},
     pages = {119-125},
     mrnumber = {MR0350114},
     zbl = {0325.34034},
     url = {http://dml.mathdoc.fr/item/700084}
}

Neuman, František. Oscillation in linear differential equations, dans Proceedings of Equadiff III, GDML_Books,  (1973), pp. 119-125. http://gdmltest.u-ga.fr/item/700084/