ayment of fund and its quality in commerce is regarded as an important matter so that it has induced the legal systems to systematize it and provide documents for it and dedicate certain regulations to it. In commercial law of Iran, bill of exchange promissory note, and cheque, through passing regulations, have been considered as commercial instruments and even though there are differences among them, they are regarded as devices of payment. Among these three instuments, bill of exchange and cheque are payment order
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