“…Meanwhile, there also have been numerous research for second order neutral functional difference equations, due to the comprehensive use in natural science and theoretical study. Some interesting recent results on the oscillatory and asymptotic behavior of second order difference equations can be found in [12,13,14,15,16,17,18,19,20,21,22]. However, it seems that there are no known results regarding the oscillation of second order difference equations of type (1).…”