“…So the asymptotic properties of the solution to (5.1) are those of the convolution g * H(t), which, under various assumptions, have been studied by several authors [12,13,8,2,1]. Some properties of X(t) were later rediscovered in a slightly more general setting [15,Theorem 5.1]. Usually, assertions about the asymptotic behavior of g * H(t) are called key renewal theorems.…”