[经] commercial documentary letter of credit

shāng yè gēn dān xìn yòng zhuàng ㄕㄤ ㄧㄝˋ ㄍㄣ ㄉㄢ ㄒㄧㄣˋ ㄩㄥˋ ㄓㄨㄤˋ