Hey anonymous,
I believe you will be able to find many at the University case books available to download in the internet (and I think also in other posts!) - it's quite a traditional sector for consulting firms, so not so difficult to find them.
If you're applying to MBB firms as a specialist, you should expect to be tested at a signifcantly deep level of industry expertise, so you should know the major trends, dynamics, main players, business model, ideas on how to increase revenues/decrease costs, etc
Best
Bruno