Iterative oscillation tests for difference equations with several   non-monotone arguments
  We consider difference equations with several non-monotone deviating arguments and nonnegative coefficients. The deviations (delays and advances) are, generally, unbounded. Sufficient oscillation conditions are obtained in an explicit iterative form. Additional results in terms of $\liminf $ are obtained for bounded deviations. Examples illustrating the oscillation tests are presented. 
Elena Braverman, George E. Chatzarakis and Ioannis P. Stavroulakis
math.DS