i’m a credit analyst on European Banks. For books, I would recommend ‘the bank credit analysis handbook’ by Jonathon Golin and Philippe Delhaise. It gives a great understanding of the balance sheet, funding structure, capital requirements and income statement.
Might be worth trying to get hold of a moodys paper or fitch paper on couple of Banks which some publish on their investor relations website.
You thinking of any banks in particular? Or any countries?