Economic is derived from Economy. Economics is derived from Economic. Economics is related to Demand. 
Pay is related to Expense. Expense is related to Sheet. Sheet is a type of Artifact. Sphere is a type of Artifact. 
Economy <--DerivedFrom-- Economic <--DerivedFrom-- Economics <--RelatedTo--> Demand 
Pay <--RelatedTo--> Expense <--RelatedTo--> Sheet --IsA--> Artifact <--IsA-- Sphere 