[en] The paper deals with transfer reactions when used to test the configurations of the excited states of the residual nucleus compared with the target nucleus. They should lead to a better understanding of the structure of nuclei with implications on nuclear models. A simple and concise account is given of the quantum-mechanical treatment used for this type of scattering system. After the distorted-wave Born approximation has been obtained, the various approximations usually adopted in the calculations of the scattering amplitude are discussed. (author)