Asymptotic behavior of solutions to a class of non-autonomous delay differential equations

In this paper, we study the asymptotic behavior of solutions of a class of non-autonomous delay differential equations. These equations have important practical applications and generalize those on which Bernfeld and Haddock conjectured that each solution of the equations tends to a constant. It is shown that every solution of the equations is bounded and tends to a constant as t→+∞t→+∞, which improves and extends some existing ones.