To actually use resources, most organizations will require a formal signed document to authorize the usage. We will call this document a Work Order.<br/>This model uses the Order Pattern by Riehle [Order Pattern]. Figure 3 shows that a WorkOrder may have many WorkOrderItems associated with it. These items would relate to lines on the order.<br/>Each WorkOrderItem may then have zero or more Fulfillments associated with it.<br/>Note that the WorkOrderItem may not equal the WorkOrderFulfillment as there may have been a substitution.<br/>e.g. 3 buckets of red sand on the Order, but 3 buckets of orange sand (an allowable alternative) actually sent<br/>