Oscillation theorems for certain nonlinear differential equations with deviating arguments Said R. Grace, Bikkar S. Lalli (1986) Czechoslovak Mathematical Journal Similarity:
Note on the oscillation of linear delay differential equations Rudolf Oláh (1980) Archivum Mathematicum Similarity:
Oscillation theorems for second order nonlinear delay inequalities Ján Seman (1989) Mathematica Slovaca Similarity: