Only some places where these treaties and agreements are republished are considered "official" and having a binding version of that agreement. So, even if you find a republished version through Google, that may not mean it is a binding replication of the text. Frequently, they are published officially online through particular websites sponsored by the international organization(s) that created the agreement.
Describe the payment terms for the transaction, including the total amount for the service, how much and when the deposit is due and how much and when the final payment is due. Spell out a time line or milestones. Include specific dates for the delivery of parts of the service or the final deadline for the service to be complete.