Accounts Payable Policy

I have been assigned the task of developing an Accounts Payable Policy for the bank; does anyone have such a Policy that they would be willing to share that I can use as a guide. I am not a policy writer, but want to ensure I have covered all the appropriate topics. Thank you.

Basically, you want to detail:
1. Purchasing requisitions and approvals
2. Vendor management
3. Expense (invoice) approval
4. Expense processing (general ledger coding) and recording
5. Expense payment and invoice cancellation
6. A/P reconciliation
7. Other (i.e. Employee expense reimbursements, capital expenses, physical security of checks, etc.)

I hope that helps!