“…Among the proposed approaches, we mention: the popular Shake-Rattle method [1,37], later proved to be symplectic [30], higher order methods obtained via symplectic PRK methods [24], composition methods [35,36], symmetric LMFs [18], methods based on discrete derivatives [19], local parametrizations of the manifold containing the solution [3], projection techniques [38,41]. As additional references, we refer to [20,28,31,32,39] and to the monographs [4,21,23,29], and references therein. In particular, in [31] different methods, such as penalty methods, are analyzed and compared, whereas in [32], following a route akin to [13], an extra parameter is added to the methods to enforce the constraints.…”