Another possibility is the Breviarium Romanum . In some 19th-century reprints found on Internet Archive or Google Books:
Note: The "ps" is pronounced as in "psalm." Do not drop the P.
"O Redemptor Sume Carmen" is a sacred Latin hymn traditionally sung during the on Maundy Thursday. It is performed as the processional for the blessing of holy oils—the Oil of the Sick, the Oil of Catechumens, and the Sacred Chrism—by a bishop. Review of "O Redemptor Sume Carmen" (Liturgy & Arrangement)