Sample Deal Intro Referral Agreement? ('Bird Dog' in real estate)

Does anyone have a sample agreement they used to pay a referral fee upon closing for intros to off-market deals? I want to pay a referral fee to accountants, Vendors, friends, etc. who introduce me to a potential seller if we end up buying the business. This is extremely common in real estate and it's called bird dog agreement but i wanted to see one for this scenario if someone had one.