房地产课程问题

水天蓝

正在学房地产课程，有个题怎么也找不全答案， 希望坛子里的达人指点下：
问题是：For the agency to be entitled to commission and recovery of marketing expenses , list four key documents that would now be in the completed sale file?

我有了三个： sale authority form, contract of sale and accounts sale. 还有一个是什么就怎么都找不到答案。