[en] We consider the transition matrix element for the removal of an α-particle or a nucleon from a nucleus. Our simple model yields, in two limiting cases, different reduced amplitudes for the bound state functions of the removed particle. We shall call these amplitudes the conventional, Gsub(conv), and the new, Gsub(new), respectively. The transition between these limits is contained in the model. The parameter which described the transition is the momentum transferred to the removed (or added) particle. (orig.)