[经] commercial documentary letter of credit

shāng yè yā huì xìn yòng zhuàng ㄕㄤ ㄧㄝˋ ㄧㄚ ㄏㄨㄟˋ ㄒㄧㄣˋ ㄩㄥˋ ㄓㄨㄤˋ