(define p (list cons +))
(define q '(cons +))
(define r (list 'cons '+))
((car p) 3 4)                           ;(3 . 4)
((cadr p) 3 4)                          ;7
((car r) 3 4)                           ;'cons is geen procedure
((cadr q) 3 4)                          ;'+ is is geen procedure