Jerome, Saint. Praefatio Hieronymi in Librum Psalmorum in Patrologiae cursus completus. Series Latina (Patrologia Latina) 29.117-120

[Letter from Saint Jerome to Paula and Eustochium]
Jerome sends his corrected translation of the Psalms to Paula and her daughter Eustochium, with a list of the critical marks he used in it to distinguish what differs in the Hebrew from the Septuagint.
Online at Epistolae (Duplicate) (See also Bibliographia record).