[1] T. Kusano, M. Naito:
Comparison theorems for functional differential equations with deviating argument. J. Math. Soc. Japan 33 (1981), 509–532.
DOI 10.2969/jmsj/03330509 |
MR 0620288
[3] J. Ohriska:
Oscillation of differential equations and $v$-derivatives. Czechoslovak Math. J. 39(114) (1989), 24–44.
MR 0983481 |
Zbl 0673.34044