I too have desired to see these for some time. I have been told that they were equal or better than the typical gregorian tones, which is fascinating possibility. It's frustrating that the ambrosian office books difficult to find.
Antiphonarium Ambrosianum of the British Museum (XIIth century) Codex Additional 34209 – Transcription Antiphonarium Tonale Missarum (XIth century) Codex H. 159 of the Bibliothèque de l’Ecole de Médecine de Montpellier
You can find them in the Liber Vesperalis juxta ritum Sanctae Ecclesiae Mediolanensis, pp. 818-840. I advise you to read the introduction closely, because the system of psalm tones in the Ambrosian rite is quite different from the eight Gregorian modes.
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