The time integral appearing in the paper is not really a memory effect. It is just a summation of infinitesimal increments, not much different from a non-relativistic formula for a traveled distance as function of time $$x(t)=\int dt\,v(t),$$ where ##v(t)## is a time-dependent velocity.Thank You and I am sorry for lack of clarity. Under the effect of memory is meant: the coming behavior of a body depends on the previous history of this body. In common worldview it is enough to know position and velocity of a body to know its future evolution. Here it is not the case, am I right? I understand, that it is not easy question for the rapid answering. Author of this "memory" remark is Dmitri Martila.