The audit of accounts payable includes substantive procedures. Substantive procedures for accounts payable include:

• Obtain or prepare a trial balance of accounts payable as of the balance sheet date and reconcile with the general ledger.
• Vouch balances payable to selected creditors by inspection of supporting documents.
• Reconcile liabilities with monthly statements from creditors.
• Confirm accounts payable by direct correspondence with vendors.
• Perform analytical procedures for accounts payable and related accounts.
• Search for unrecorded accounts payable.
• Perform procedures to identify accounts payable to related parties.
• Evaluate proper balance sheet presentation and disclosure of accounts payable.

Briefly describe the purpose of three substantive procedures for accounts payable?