Aperiens Petrus os suum dixit

Source: 
Worcester, Cathedral - Music Library, F.160 (olim 1247) (with hymnal)
Folio: 
228r
Sequence: 
12
Feast: 
Petri, Pauli
Office/Mass: 
M
Genre: 
A
Position: 
2.2
Cantus ID: 
001445
Mode: 
8
Differentia: 
1
Differentia database: 
1--k-k-j-k-h-g--4 118a
Addendum: 
P: 326