求助翻译。客户单证中这么一句话怎么理解

commercial invoice – must he link to julong contract number and our po number o? ?packing list – must he link to julong contract number and our po number o? ?seaway bill – must he link to julong contract number and our po number 客户对我们的单据要求里有这些 julong 是我们公司 请问里面he link to 指的是这些单据是要写上我司合同号和客户合同号，还是说要和合同号相对应，有 很苦恼客户的这种表达，要是单据上显示合同号，直接用he就可以了 为啥是link to 呢 求高人解答