No need, but if it is coming from a sale, and i suggest you keep a copy of these email exchanges to include in your application when you make it.

• 如果这笔资金是来源于一笔出售合同,这样就不必要一定要个月。并且我建议你在申请签证的时候,把交易的电子邮件通讯记录附在文件包中。