Okla. Stat. tit. 12A, § 2-323
Oklahoma Code Comment
In some domestic shipments, and in most foreign shipments, bills of lading are issued in sets, usually of four. All parts of the set cover the complete shipment, and are original bills. Parts of the set travel with the goods, and the other parts are sent by other means of transportation. This is done so that there will be evidence of the shipment available in the event of casualty to other parts. The presence of several original bills, however, creates the problem of bona fide purchasers of parts, which is governed by Article 5 of the Commercial Code. The problem of presenting the bills for payment is governed in this section.