Source of example in Choralis Constantinus II: Probably the Choralis print.
Choralis Constantinus II contents:
Character of the Choralis Constantinus II example:
The example is without text. Its purpose is to illustrate alternating perfect (white) and imperfect (black) breves in the tenor. There is a resolution of the tenor in ₵ with alternating dotted and undotted breves.