甲公司和乙公司系购销关系,因双方发生欠款纠纷,甲公司被乙公司诉至法院。因甲公司所供的货物是建材,所以合同在履行过程中,还分别涉及到原始供货商两工厂和最终用户丁建筑公司。在诉讼过程中,甲公司发现能够证明自己已供货的两张进货单和提供单需 Company A and Company B are buying and selling relationships, because of the arrears dispute between both parties, Company A was sued by Company B to the court. Because A company for the goods is building materials, so the contract in the implementation process, respectively, involving the original supplier of two factories and end-users Ding construction company. During the course of the proceedings, Company A found two purchase orders and supply orders that could prove that they had been delivered