The following report shows the amount of overlap between pairs
of works within a set, after removing those overlaps that also
occur when comparing the works with a second set of works.
The content of each work, in comparison with another work, has
three categories:
common
Text that is shared between both works, and that also occurs
in at least one works in the second set of works.
shared
Text that is shared between both works, and that does not
occur in any of the works in the second set of works.
unique
Text that is unique to the work, occuring neither in the
other work, nor in any of the works in the second set of
works.