How you can post the 2015 year expenses bills on 2016 Accounts?

If the expenses is known to prior to closing of annual accounts we make make a provision in books,Debit  the relavant expenses A/C Cr Outstanding liability.This has to be taken to liability side of the balance sheet.If we come to know about this after closure of annual accounts we can debit to prior period expenses.This has to be approved by auditors.If the volume is very big this may be disclosed in the balance sheet by qualification.Thanks for inviting.