A method of reversing a plurality of erroneous invoices proffered by a plurality of vendors/suppliers. The method comprises providing a master database for inputting a plurality of vendor invoices, storing a cancellation request for each of the plurality of erroneous invoices in a response database,...http://www.google.es/patents/US7774352?utm_source=gb-gplus-sharePatente US7774352 - Method of reversing an erroneous invoice
