“…The subsequent examples of the most prominent textbooks on the topic are those by Szabó and Babuška [71], Schwab [59], and Demkowicz et al [24,26], where the historical background and the extended survey of related bibliography can be found. In the meantime the methods have been applied to various problems of the applied mechanics (compare [17,27,40,43,[45][46][47]56,57,84], for example). Also some extensions of the hp approach to other numerical techniques have appeared.…”