The first half of the antiphon O admirabile commercium (Cantus ID 003985) is quoted in the T (passage: "O admirabile ... et procedens homo") and partially in the C (incipit):
1--efd-dc--f--f--fg--g--g--gf--gh---gf--f--f--gh--f--g--f--g--gh--f--f--4
"O admirabile commercium creator generis humani"
1--f--f--fhijh--g--j--h--g--f--f--g--f--f--4
"animatum corpus sumens de virgine"
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"nasci dignatus est et procedens homo" (http://cantusindex.org/id/003985)
The next part of the antiphon O admirabile commercium (Cantus ID 003985) is quoted in the C (passage "sine semine")
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"sine semine" (http://cantusindex.org/id/003985)
The last part of the antiphon O admirabile commercium (Cantus ID 003985) is quoted in the T (passage "largitus est" ... end)
1--cd--f--f--f--gh--g--h--hk--hg--h--f--f---4
"largitus est nobis suam deitatem" (http://cantusindex.org/id/003985)
I Fiamminghi IV: O admirabile commercium. Brumel, Regis, Mouton, Josquin. Cappella Pratensis - Rebecca Stewart, Ricercar 207572
Clefs vary in the sources.
See also The Josquin Research Project.