Regular is a different concept from Premium. Premium is a type of Bonus. Bonus is related to Free. Free is related to Democracy. 
Nurse is a type of Treat. Nurse is related to Profession. 
Regular <--DistinctFrom--> Premium --IsA--> Bonus <--RelatedTo--> Free <--RelatedTo--> Democracy 
Treat <--IsA-- Nurse <--RelatedTo--> Profession 