S.D. CODIFIED LAWS §5-18A-1. Definition of terms
Terms used in this chapter and chapters 5-18B, 5-18C, and 5-18D mean:
(21) “Purchasing agency,” any governmental body or officer authorized by law, administrative rule, or delegated authority, to enter into contracts;
S.D. CODIFIED LAWS5-18A-37. Cooperation and agreements with other state and federal purchasing agencies.
Any purchasing agency may enter into agreements with purchasing agents in this or any other state or the United States government under which any of the parties may agree to participate in, administer, sponsor, or conduct purchasing transactions under a joint agreement or contract for the purchase of supplies or contractual services. A purchasing agency may cooperate with purchasing agencies and other interested parties in any other state or the United States government to develop uniform purchasing specifications on a regional or national level to facilitate cooperative interstate purchasing transactions.
Link to the full statute can be found here: legis.state.sd.us/statutes/DisplayStatute.aspx?Statute=5-18A-37&Type=Statute