There are hundreds if not thousands of books at QMU that contain case studies. To find them, go to the Library Catalogue and try the following different searches:
case stud* - to search for books containing case AND (study or studies) where the asterisk searches for various word endings or plurals
business case* - to search for books containing business AND (case or cases)
The word business above can be replaced with more specific terms: management, leadership, marketing, finance, accounting, strateg* (for strategy or strategic), ethic* (for ethic, ethics or ethical) etc.