The beginning of the antiphon Quando natus est (Cantus ID 004441) is quoted in C and T (opening)
1--e--eed--g--hk--k--k--j--h--gh--j--h----4
"Quando natus est ineffabiliter" (http://cantusindex.org/id/004441)
A next part of the antiphon Quando natus est (Cantus ID 004441) is quoted in the T (passage "tunc ... scripturae"):
1--g--h--j--k--hgh---ghg--e--e----4
"tunc impletae sunt scripturae" (ibid.)
The next part of the antiphon Quando natus est (Cantus ID 004441) is quoted in the T (passage "sicut pluvia (2nd time) ... descendisti"):
1--g--h--k--j--klk--j--kj--h--h--g--k--h---4
"sicut pluvia in vellus descendisti" (ibid.)
The next part of the antiphon Quando natus est (Cantus ID 004441) is quoted in the T (passage "ut salvum ... humanum"):
1--k--k--k--k--jh--g--hgf--g--ghg--e--e--4
"ut salvum faceres genus humanum" (ibid.)
The last part of the antiphon Quando natus est (Cantus ID 004441) is loosely quoted in the T (passage "te laudamus ... noster"):
1--hjh--g--gf--ef---g--gf--e--e--4
"te laudamus deus noster" (ibid.)
See also The Josquin Research Project.