The 1956 edition of the OHS (Ordo Hebdomadae Sanctae Instauratus) book for the Holy Week Rites retained the Neo-Psalter (of Pius XII) for the featured parts of the Divine Office.
Thus for the concluding part of the Easter Vigil Mass, the Matin-Lauds Office part has the Neo-Psalter version of the Benedictus. However, most scholas sing the Vulgate version (a reversion authorized by Pope John XXIII in 1958) and the majority of priests are also familiar with this too.
Thus, rather than using a Liber Usualis (which with its small print is difficult to read at the altar), this missal-size Matin-Lauds insert has been produced, which can either be inserted into the book, or even placed in it's own folder (and switch out with either the OHS or missal during this time).
