service(Person, Service) :- book_overdue(Person, Book),
                            basic_service(Service).
service(Person, Service) :- general_service(Service).
 
basic_service(reference).
basic_service(inquiries).
 
special_service(borrowing).
special_service(interlibrary_loan). 
 
general_service(X) :- basic_service(X).
general_service(X) :- special_service(X).
 
book_overdue(jones, war_and_peace).
book_overdue(jones, oliver_twist).