Incipit of the antiphon Da pacem domine (Cantus ID 002090) quoted in transposition in C and T1 (opening):

1--d--c--d--f--g--f---e--f--g--fe--d--d---4

"Da pacem domine in diebus nostris" (http://cantusindex.org/id/002090)

Verse 1a and 1b of the sequence Ave Maria, gratia plena (Cantus ID 850309) quoted in transposition in the corresponding passages of T1 and T2 (alternating):

1--g--g--g--hj--g----g--e--d--eg--g---4

"Ave Maria, gratia plena
dominus tecum, virgo serena"
(GOEDE 1965, No. 38)

Typical recitation formula used in the passage "Ecce ancilla domini fiat mihi secundum verbum tuum", quote distributed between T1 and T2:

1--k--k--k--k--k--h----k--k--k--k--k--k--h---4

E.g. "Dominus vobiscum. Et cum spiritu tuo." (GT 820)

Verse 1a and 1b of the sequence In honore matris dei (which was sung on the tune of Sospitati reddit aegros) quoted in transposition in the corresponding passages of T1 and T2 (alternating):

1--d--h--h--g--f--e--g--h----d--f--e--d--c--d--d---4

"In honore matris dei / Et eius memoria
Decantemus omnes ei: / Ave, plena gratia."
(from Sospitati, http://cantus.uwaterloo.ca/chant/403479)