A volume can contain more than one legal text
The University of Michigan’s Islamic manuscripts collection covers jurisprudence together with many other subjects. It is a useful setting in which to consider a basic bibliographic problem: a volume on a shelf and a work named in a bibliography are not necessarily the same unit.
A single physical volume may carry several works; a work may also survive in several copies. A legal historian’s count can therefore change according to the unit being counted. The distinction should be explicit before a catalogue search is turned into a statement about the size or influence of a textual tradition.