During the last few years, a number of articles has been appeared in the literature, which are motivated by the old but very interesting papers by Driver [7, 8] and Driver, Sasser and Slater [10] dealing with the asymptotic behavior and the stability of the solutions of delay differential equations. See [2, 4, 5, 12, 13, 17-21, 27-41, 44]. These articles are concerned with the asymptotic behavi...