SMSA prides itself on having up-to-date information on the processing and current location of each shipped item. To do this, SMSA relies on a company-wide information system. Shipped items are the heart of the SMSA product tracking information system. Shipped items can be characterized by item number (unique), weight, dimensions, insurance amount, destination, and final delivery date.

Shipped items are received into the SMSA system at a single retail center. Retail centers are characterized by their type, unique ID, and address. Shipped items make their way to their destination via one or more standard SMSA transportation events (i.e., flights, truck deliveries). These transportation events are characterized by a unique schedule Number, a type (e.g, flight, truck), and a delivery Route.

Please create an Entity Relationship diagram that captures this information about the SMSA system. Be certain to indicate all of the entities, attributes, relationships and cardinality constraints.