Business cases are summaries of real life business scenarios, or fictitious accounts of a business situation or dilemma.
There are publishers, such as Harvard Business School Press, which produce and sell cases for teaching and learning purposes.
There are also other sources of case studies, including books, articles, academic research and free internet sources.

Case studies in books
Many books contain case studies in their contents. Combine "case studies" with your chosen company or topic in a Catalogue keyword search.

Examples:
   "case studies" sustainability
   "case studies" "corporate responsibility"
   "case studies" "New Zealand" tourism

You can sometimes find relevant material in Google books by searching with the phrase "case study" or "case studies" and a keyword.